ALBERT

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 578〈/p〉 〈p〉Author(s): Yadan Guo, Chenxi Li, Yiqin Guo, Xuegang Wang, Xiaomeng Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Graphitic carbon nitride (g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉) is a new type of nonmetal polymeric semiconductor photocatalyst for removal of pollutants. To overcome the low BET surface and the low electron–hole recombination rate of the g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 photocatalysts, we successfully synthesized g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/Na-bentonite composites using an ultrasonic-assisted method. The XRD showed that the composite was composed of g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 and Na-bentonite. The analyses of TEM and XPS indicated that graphite carbon nitride was successfully intercalated on Na-bentonite via the ultrasonic-assisted strategy, and the g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/Na-bentonite nanocomposites presented remarkable light absorption capacities and mesoporous structure observed by UV–vis DRS and BET method. In addition, the as-prepared composites can be used for the photocatalytic removal of single RhB or Cr(VI), and the efficiencies of the Cr(VI) reduction are increased from 53.2% to 88.6% in RhB/Cr(VI) mix-system. Superior stability and high efficiencies of g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/Na-bentonite composites were also exhibited for up to 4 cycles. The photocatalytic enhancement was due to the strong adsorption and the higher charge separation efficiency of as-prepared g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/Na-bentonite composites.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719306065-ga1.jpg" width="219" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 578〈/p〉 〈p〉Author(s): Lifeng Chen, Zhen Qian, Liang Li, Meilong Fu, Hui Zhao, Lipei Fu, Gang Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Water production is getting worse along with the continuous water injection in the reservoir with fracture, but common hydrogels cannot be successfully applied for water shutoff due to its poor resident ability in fracture. In this work, an interpenetrating network hydrogel has been developed innovatively by polyvinyl alcohol (PVA) fiber and common polyacrylamide (PAM) hydrogel. Plugging ability, long-term thermal stability and the interaction between PVA fiber and hydrogel were detailedly studied. Results show that PVA fiber is beneficial to the stability of the PAM hydrogel, and the syneresis rate can be decreased from 30% to 3% on the 120〈sup〉th〈/sup〉 day. PVA fiber accelerates the hydrogel gelation, and the high concentration of fiber leads to good hydrogel strength. PVA fiber increases the amount of the bound water in hydrogel, leading the hydrophilcity increase of hydrogel. An interpenetrating network is formed on the micrometer level, resulting from the three-group crosslinking among polymer, cross-linker and fiber. Compared with common PAM hydrogel, the interpenetrating network hydrogel has better water shutoff effect and EOR performance. Core flow experiment and micromodel test show that the interpenetrating network hydrogel forms an effective bridge in fracture, and it is hard to be moved due to the water washing. The introduction of fiber to hydrogel is an innovative research, which not only improves the water shutoff effect of hydrogel in fracture, but also provides reference to increase the performance of drilling fluid, fracturing solution and EOR polymer utilized in petroleum engineering.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Micropresentation of synergistic effect of PVA fiber on PAM solution (A, B) and hydrogel (C, D).〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719305928-ga1.jpg" width="252" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 578〈/p〉 〈p〉Author(s): Krzysztof Kolman, Zareen Abbas〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Molecular dynamics (MD) simulations provide molecular level information about the interaction of organic molecules with the solid surfaces. There has been much development of this method to simulate the interaction of organic molecules with neutral surfaces but relatively less information is available regarding the interactions with charged surfaces. In this study we have developed MD model for the charged silica surface and have investigated the interactions of different benzoic acid derivatives with the charged silica surface in pure and saline water at acidic, neutral and basic pH. The investigated molecules were 2,3-dihydroxybenzoic acid (23DHBA), 3,4-dihydroxybenzoic acid (34DHBA), 1,2,4-benzenetricarboxylic acid (BTCA) and phthalic acid (PHTHA). To simplify the analysis of results, three different simulation systems were considered. Clustering simulations showed how molecules aggregate in solution, pulling simulations provided quantitate information regarding the interactions of single molecule with the silica surface, whereas adsorption simulations focused on the adsorption of multiple molecules on the surface. In general, at pH 2–3, all investigated molecules were clustering and were attracted towards the surface. At pH 7, due to arising electrostatic repulsion, the interactions became weaker which prevented 23DHBA, 34DHBA and BTCA from clustering, however, they continued to adsorb on the silica surface. The adsorption of 23DHBA and 34DHBA decreased significantly at pH 9–10 due to electrostatic repulsion between the molecules and charged silica surface, while BTCA adsorbed slightly stronger due to interactions with ions close to the surface. PHTHA molecules behaved differently by clustering stronger and adsorbing weaker at higher pH. The results of MD simulations presented in this work by using pulling and adsorption approaches provide possibility to compare the results with experimental data.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719301748-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 578〈/p〉 〈p〉Author(s): José G. Parra, Héctor Domínguez, Yosslen Aray, Peter Iza, Ximena Zarate, Eduardo Schott〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Structural characteristics, interfacial distribution and molecular interactions of the components of the CO〈sub〉2〈/sub〉(gas)/SDS/water/SDS/CO〈sub〉2〈/sub〉(gas) systems as a function of the CO〈sub〉2〈/sub〉(gas)/water interface coverage by the SDS surfactant to different amounts of the CO〈sub〉2〈/sub〉 were studied with molecular dynamics simulations and the NVT ensemble. Initially, the repulsive nonbonding parameter between the water oxygen and CO〈sub〉2〈/sub〉 oxygen was adjusted to improve the prediction of the solvation free energy, solubility of the CO〈sub〉2〈/sub〉 gas in water and the behavior of the CO〈sub〉2〈/sub〉(gas)/SDS/water/SDS/CO〈sub〉2〈/sub〉(gas) systems at molecular level. Our results show that the stability of the studied foams can be improved incrementing of the vapor/water interface coverage with the SDS surfactant and the amount of CO〈sub〉2〈/sub〉 in the system. With the highest interface coverage, the sulfate group has a molecular array more compact at the interface. Furthermore, CO〈sub〉2〈/sub〉 gas have a reduction of the diffusion across of the hydrocarbon chains to the water layer with an increment of the number of CO〈sub〉2〈/sub〉 molecules in the system, indicating a behavior more hydrophobic of the CO〈sub〉2〈/sub〉 gas. The tendencies obtained of the simulations are consistent with the reported experimental results.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719305989-ga1.jpg" width="239" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 578〈/p〉 〈p〉Author(s): M. Jinish Antony, C. Albin Jolly, K. Rohini Das, T.S. Swathy〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report here the synthesis of polyaniline (PANI) nanomaterials using sodium bis (2-ethylhexyl) sulfosuccinate (AOT) micelles assisted chemical oxidative interfacial polymerization. We have employed two interfaces (chloroform-water and hexane-water) and two oxidizing agents (ammonium persulfate and ferric chloride). The anionic surfactant sodium bis (2-ethylhexyl) sulfosuccinate (AOT) forms normal micelles in aqueous solution and reverse micelles in hydrophobic solvents like hexane or chloroform. The factors influencing the properties and morphologies of polyaniline nanomaterials such as monomer: surfactant ratio, monomer: oxidant ratio, types of interfaces and oxidants used have been studied. Powder X-ray diffraction of the polyaniline nanomaterials have revealed that polyaniline samples were semi-crystalline in nature. Morphology of polyaniline samples studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have revealed that most of the polyaniline nanomaterials synthesized using ferric chloride possess spherical nature, whereas polyaniline samples synthesized using ammonium persulfate (APS) possess short nanofibers especially at lower aniline/AOT mole ratio in feed (12.5–6.5). The four probe electrical conductivity of the samples were found to be of the order of 1.8 × 10〈sup〉−1〈/sup〉 to 8.6 × 10〈sup〉−1〈/sup〉 S/cm. Thermal stability of the polyaniline samples recorded by thermogravimetric analysis (TGA) have revealed that polyaniline samples were thermally stable up to 275 °C for 10% weight loss. Interfacial polymerization of aniline monomer using reverse micelles of AOT in hexane phase and ammonium persulfate as oxidizing agent in aqueous phase have been proved to be efficient method for the synthesis of short polyaniline nanofibers.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719306090-ga1.jpg" width="316" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 578〈/p〉 〈p〉Author(s): Feng Zhao, Shibin Wang, Xin Shen, Jianchun Guo, Yuxuan Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Inhibiting acid-rock reaction rate is an important key in the field of acid fracturing. Based on the acid-rock reaction mechanism and the performance characteristics of surfactant, the surfactant is applied to cover the rock surface for forming an adsorption layer, which can keep H〈sup〉+〈/sup〉 from contacting the surface of rock during acid fracturing. In this paper, a series of cationic Gemini surfactants with different hydrophobic chain length are synthesized (C〈sub〉n〈/sub〉-4-C〈sub〉n〈/sub〉, n = 12, 14, 16).The surface tension, adhesion work, and AFM are used to investigate the effect of hydrophobic chain length and concentration of surfactant on surface activities, adsorption morphology and adsorption capacities. The static acid-rock reaction rate is measured and the surface of the rock plate is digitally characterized by 3D scanning. The results show that Gemini surfactants have the high surface activities. It can be recognized from AFM that as the length of the carbon chain increases, the aggregation of Gemini surfactants on the surface to form micelles becomes more and more obvious, resulting in a decrease in the density and area of the adsorption. However there are few differences for adsorption capacities. Therefore, 12-4-12 can restart H〈sup〉+〈/sup〉 most efficiently. This conclusion is proved by static acid-rock reaction. In addition, H〈sup〉+〈/sup〉 only reacted with the rock from the micro fractures of the adsorption layer formed by 12-4-12, the surface morphology of the rock plate after etching is the best rugged. In conclusion, it is believed that using the Gemini surfactant to form an adsorption layer on the rock surface is a new approach for inhibiting acid rock reaction rate and has great potential in oil field application.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Inhibiting acid-rock reaction rate is an important key in the field of acid fracturing. The morphology of the surfactant on the rock controls the rate between acid and rock. The properties of the different chain length surfactant form different layered structure on the substrate. 12-4-12 can play an efficacious role to adsorb on the rock surface to prevent H〈sup〉+〈/sup〉 from contacting the surface of rock.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719306119-ga1.jpg" width="295" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 578〈/p〉 〈p〉Author(s): Zhao Mu, Jianhao Hua, Sai Kumar Tammina, Yaling Yang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In current investigation, we synthesized a new Cu, N co-doped carbon dots/Ag〈sub〉3〈/sub〉PO〈sub〉4〈/sub〉 (Cu, N-CDs/Ag〈sub〉3〈/sub〉PO〈sub〉4〈/sub〉) nanocomposite by one-step thermolysis and precipitation method. In addition, we evaluated the activity of Ag〈sub〉3〈/sub〉PO〈sub〉4〈/sub〉 and Cu,N-CDs/Ag〈sub〉3〈/sub〉PO〈sub〉4〈/sub〉 nanomaterials in degrading an environmental pollutant called neutral red under visible radiations. Compared to the pure Ag〈sub〉3〈/sub〉PO〈sub〉4〈/sub〉, Cu, N-CDs/Ag〈sub〉3〈/sub〉PO〈sub〉4〈/sub〉 had shown high degradation efficiency by more than 25% and shown good recyclability. The synthesized nanocomposite was characterized by XRD, HRTEM, FT-IR, Raman and XPS techniques. The optical property of Cu, N-CDs/Ag〈sub〉3〈/sub〉PO〈sub〉4〈/sub〉 nanocomposite was examined with UV–vis DRS (Diffuse Reflectance Spectroscopy). And the excellent photocatalytic performance of this Cu, N-CDs system was ascribed to the increased conversion of ·O〈sub〉2〈/sub〉〈sup〉−〈/sup〉 under visible light irradiations and effective separation of electron-hole pairs, results in inhibited photocorrosion of the system. Also, this nanocomposite could successfully degrade the neutral red dye (mention the concentration) about 95.5% under LED irradiations within 60 min.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719306193-ga1.jpg" width="222" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 578〈/p〉 〈p〉Author(s): Juan David Beltrán, Camilo Eduardo Sandoval-Cuellar, Katherine Bauer, María Ximena Quintanilla-Carvajal〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Liposomes are spherical vesicles which can be used as encapsulation systems for transporting and releasing many biocomposites which can be affected by conditions in the gastrointestinal tract; such affectation means that the dominant degradation mechanisms and the factors influencing such degradation must be identified by means of digestion studies. This study was thus aimed to evaluate the physical stability and intestinal digestibility of nanoliposomes (NLs) produced by microfluidization (MF) and ultrasound (US) for high oleic palm oil (HOPO) encapsulation. A standardized 〈em〉in vitro〈/em〉, three-stage (〈em〉i.e.〈/em〉 oral, gastric and intestinal) static model of the gastrointestinal tract was used which had been published by the INFOGEST research network. No statistically significant changes were observed concerning any of the properties regarding stability during the oral phase; however, both types of NL studied here became destabilized during the gastric phase by environmental conditions, such as acid pH and high ion concentration. This was reflected by increased average particle size, the polydispersity index and the Z potential. Decreased particle size was observed during intestinal digestion regarding both technologies compared to gastric phase. MF-produced NLs were larger than US-produced ones during this phase. Intestinal enzymes degraded the system’s triglycerides, leading to 116.04 ± 2.62%w MF and 80.39 ± 2.26%w US free fatty acid release.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719305862-ga1.jpg" width="389" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 578〈/p〉 〈p〉Author(s): Chengwei Wang, Lili Ma, Qingkun Wen, Baoxiang Wang, Rongjiang Han, Chuncheng Hao, Kezheng Chen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, an electrorheological (ER) fluid containing titanium oxide@ H〈sub〉2〈/sub〉Ti〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 nanotube core/shell nanocomposite was prepared via the combination of hydrothermal and solvo-thermal method. The morphological evolution was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. Furthermore, the structural characteristics of the as-obtained core/shell nanoparticles were confirmed by x-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) and nitrogen adsorption measurements respectively. Titanium oxide@H〈sub〉2〈/sub〉Ti〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 nanotube core/shell nanocomposite is showed to possess tube-like and core-shell structure and enhanced ER properties under external electric fields.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571930617X-ga1.jpg" width="235" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 578〈/p〉 〈p〉Author(s): Jincheng Mao, Jizhen Tian, Wenlong Zhang, Xiaojiang Yang, Heng Zhang, Chong Lin, Yang Zhang, Zhaoyang Zhang, Jinzhou Zhao〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Gemini cationic surfactants, which have two cationic surfactant molecules connected by a spacer, have received increased attention in recent years as very good thickeners for clean fracturing fluids. We synthesized four Gemini cationic surfactants with three, four, five, and six methylene groups in the spacers. Salts can promote micelle aggregation of viscoelastic surfactants (VESs) and affect their performance and we used potassium chloride (KCl) to study the performance differences of the surfactants with different spacer lengths. The results showed that the surfactant with three methylene groups in its spacer had the lowest critical micelle concentration, and when combined with KCl in solution, it had the best salt tolerance and apparent viscosity in KCl concentrations ranging from 0.2 wt% to 2.6 wt%. In addition, the solution also exhibited an excellent viscoelasticity and a tighter network microstructure, which was confirmed by SEM observation and oscillatory measurement. We conducted rheological measurements for the four Gemini cationic surfactant fracturing fluid formulations with a shear rate of 170 s〈sup〉−1〈/sup〉 at up to 100 °C. The solution with KCl and the surfactant with the shortest spacer had distinctly superior rheological properties, and its viscosity could be maintained above 58 mPa.s after 120 min. Finally, we did proppant suspension tests, gel breaking property tests, and core matrix permeability damage rate tests on the four optimized fracturing fluid systems. The solution prepared by KCl and the surfactant with the shortest spacer was found to have the most favorable properties for fracturing fluids. These results demonstrate that decreasing the spacer length of a Gemini cationic surfactant leads to better performance in fracturing fluids.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉The effect of counter-ion salt (KCl) concentrations on 21-(3,4,5,6)-21 surfactants that the surfactant solutions were transparent at low salt concentrations, but with increasing counter-ion concentrations above a peak viscosity, the phase separation occurred in all surfactant solutions. Meanwhile, this also shows that increasing the number of carbon atoms on the spacer of the surfactants lead to a greater sensitivity to the phase separation phenomenon.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719306016-ga1.jpg" width="227" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Zechen Liu, Yangchao Xia, Qingteng Lai, Maoyan An, Yinfei Liao, Yongtian Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this investigation, a mixed collector (MC) of dodecane and n-valeric acid was used to improve low rank coal flotation. Fourier transformation infrared spectroscopy (FTIR) measurements and contact angle measurements were conducted to explain flotation responses. Furthermore, using a molecular dynamics (MD) simulation, the changes of water/collector (dodecane or MC)/coal systems were studied before and after adsorption to indicate the absorption behavior and mechanism. The results showed that a better flotation performance of low-rank coal was obtained using the MC compared to a conventional collector of dodecane. The hydroxyl (-OH) or carbonyl (C = O) or carboxyl (COOH) migration of the coal with the MC was stronger than that with dodecane as a solo collector, and the MC can enhance the hydrophobicity and lipophilicity of the coal surface. MD simulation results revealed the adsorption behavior of the MC on low-rank coal surfaces. Dodecane was mainly adsorbed on the hydrophobic surface of coal, and n-valeric acid was more inclined to act on the oxygen-containing functional group of coal, i.e., a hydrophilic surface. The mobility of = dodecane molecules on the coal surface was reduced owing to the presence of n-valeric acid, which increased the lipophilicity and hydrophobicity of the low-rank coal surface, thus attracting dodecane molecules of the MC and restricting their movement, and accelerating the departure of water molecules from the low-rank coal surfaces. There was also a higher interaction energy between the MC and low-rank coal. The simulation results are in good agreement with the measured results; this effectively explains the flotation results.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719308283-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): Xing-An Luo, Pei Zhao, Hai Zhang, Shu-Yi Feng, Ke-Xian Chen, Zhong-Xiu Chen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Dietary macromolecules are often used for food formulation. Most of the published literature usually focuses on a certain polysaccharide reducing lipid digestion, but the non-specific physical effects such as the excluded volume effect of the surrounding macromolecules, which will possibly enhance the hydrolysis of lipids, is rarely discussed. As the influence of polysaccharides on the gastrointestinal fate of α-tocopherol acetate (VE-A) encapsulated in emulsion have not been conducted so far, in this research, we study the effect of crowded medium created by polysaccharides (Ficoll400) on the hydrolysis of VE-A and its bioaccessibility. The results show that the presence of Ficoll400 increased the bioaccessibility and conversion of VE-A 1.6 times that of a dilute buffer. An enzyme-catalyzed kinetic reaction rate of VE-A hydrolysis is increased up to 3.5 times. Both the improved thermodynamic conversion yields and kinetic rates of the hydrolysis of the VE-A emulsion was further observed in a synthetic macromolecule PEG2000 medium. This research improves our understanding of the crowding effect of macromolecules on VE-A/lipid emulsion digestion.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719308258-ga1.jpg" width="323" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Ping Ding, Serafim Bakalis, Zhibing Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Foaming in high viscous and non-Newtonian aqueous phase is generally difficult to be realised. In this work, a surfactant (Sodium Linear Alkylbenzene Sulphonate with alkyl chain lengths varying from C10 to C16) named LAS paste mixed with a co-polymer solution of acrylic acid and maleic acid denoted by Polymer solution was used to generate foam under conditions of sparging without or with agitation, which aims to be used as a coating material of detergent powders. The foam structure/morphology, bubble size, gas holdup and liquid drainage in such surfactant-copolymer system were investigated. It was found that two different types of foam were generated: 1) dispersed spherical air bubbles in highly viscous mixtures of LAS paste and Polymer solution with median size d50 in a range of 20 – 50 μm and gas holdup of 0.20 - 0.44 depending on LAS concentration, 2) bubbles with polyhedral structure in a mixture of LAS paste and Polymer solution diluted with water and size d50 = 7.0 ± 0.4 mm and gas holdup of 0.93 ± 0.05. The generated foam structures depended on the energy input, air superficial velocity, surfactant concentration and the liquid viscosity. Besides, they even depended on liquid mixing procedures before the foam was generated, resulting from different transfer rates from LAS paste phase to Polymer solution. The comparison of foam behaviours in such complex system and in single-phase liquid was made. For dispersed spherical bubbles, the median size has been correlated to energy input whilst for bubbles with polyhedral structure the characteristic size has been predicted by considering the balance between their buoyancy and viscous forces generated in the system. Based on the results, the mechanism of foam stabilisation is proposed.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719308052-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): Natalya Sankova, Viktoriya Semeykina, Ekaterina Parkhomchuk〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, we have studied the growing mechanism of polystyrene microspheres with a small amount of cross-linking agent (0.2–2 wt%) during dispersion polymerization (DP) in 1-butanol in presence of PVP-40 steric stabilizer. Scanning electron microscopy and dynamic light scattering showed that particles take anomalous form at first several hours due to the growth predominantly by homo- and hetero-coagulation mechanism. The duration of the coagulation process is estimated to be of about a minute. Understanding of the mechanism of particle formation in the above systems will help to overcome the problem of irreproducibility, control the preparation of anisotropic particles during DP and extend the application of these particles.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307332-ga1.jpg" width="496" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): Xiaobo Nie, Wei Jiang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A facile method is introduced to tune the aggregate morphologies of ABC triblock copolymer in selective media by combining the self-assembly and hydrogen bonding. Poly(styrene)-〈em〉block〈/em〉-poly(1,4-butadiene)-〈em〉block〈/em〉-poly(2-vinyl pyridine), abbreviated for PS-〈em〉b〈/em〉-PBd-〈em〉b〈/em〉-P2VP and used as an ABC triblock copolymer, self-assembles in toluene and methanol mixture to form discoid micelles with PBd as the disk containing part of PS domains in the core, other PS as bumps and P2VP as corona, respectively. When oleic acid (OA) is added in the assembly system, supramolecular polymer PS-〈em〉b〈/em〉-PBd-〈em〉b〈/em〉-P2VP(OA) is prepared by the hydrogen bonding between OA and P2VP of triblock copolymer. As a result, biscuit-like and mushroom-like micelles are formed with assistance of hydrogen bonding. Interestingly, the biscuit-like and mushroom-like micelles can transform reciprocally by fission and fusion mechanism through varying the volume ratio of toluene and methanol. Thus, it provides a simple and convenient approach to control the aggregate morphologies of block copolymers by tuning the hydrogen bonding and selective solvent content. The multicompartment micelles from ABC triblock copolymer may present potential applications in drug delivery, targeting, catalysis and others.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719308271-ga1.jpg" width="247" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Badr M. Thamer, Ali Aldalbahi, Meera Moydeen A, Abdullah M. Al-Enizi, Hany El-Hamshary, Mandeep Singh, Vipul Bansal, Mohamed H. El-Newehy〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Activated electrospun carbon nanofibers (A-ECNFs) with micro/mesoporous structures and high surface areas (1615 m〈sup〉2〈/sup〉 g〈sup〉-1〈/sup〉) were prepared using an electrospinning technique followed by carbonization and alkali activation. The adsorption of Congo red (CR) and methylene blue (MB) dyes by A-ECNFs from aqueous solutions was investigated and compared with those of pristine ECNFs. The textural characteristics and morphology of the prepared pristine and activated ECNFs were characterized using various techniques. The adsorption performance was found to be associated to the surface area, porosity, and surface charges of the prepared adsorbents; the nature and molecular size of the dyes; and the pH and temperature of the solution. Six nonlinear isotherm models were applied to analyze the adsorption equilibrium data, and the results showed that the adsorption behavior could be appropriately described using the Redlich–Peterson isotherm model. The kinetic results for the adsorption of CR and MB onto A-ECNFs were fitted reasonably well to the Elovich model and were fitted by a pseudo-second order (PSO) model onto the pristine ECNFs. According to the thermodynamic results, the adsorption of CR and MB onto the A-ECNFs was endothermic and spontaneous. In addition, the reusability of the A-ECNFs was evaluated over five adsorption-desorption cycles.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719308234-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): Hitomi Kobara, Kaoru Nakatsuka, Akihiro Wakisaka〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Size selected synthesis of gold nanoparticle (AuNP) was carried out by use of an ultra-fine liquid droplet as a reaction field. The ultra-fine liquid droplets were generated by electrospraying in a liquid medium. The electrospraying in the liquid medium had a great advantage over the conventional electrospraying in the air. The size of electrosprayed liquid droplets can be varied with the supplied electric voltage beyond the range of the electrospraying in the air. When the AuNPs synthesis through the chemical reduction of Au〈sup〉3+〈/sup〉 was carried out by use of this electrospraying in the liquid medium for the mixing of Au〈sup〉3+〈/sup〉 solution and the reducing agent solution, the size of AuNPs was controlled by the supplied electric voltage. Two types of reaction field equipped with a single and double electrospray nozzles were designed to be demonstrated.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉The size distribution of gold nanoparticles was controlled in the ultra-small reaction field generated by the electrospray in a liquid medium.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719308246-ga1.jpg" width="440" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): Kenji Aramaki, Misaki Fujii, Yuichi Sakanishi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉One of the major drawbacks of ionic-surfactant-based wormlike micelles (WLMs) is their poor low-temperature stability, which severely limits their application. Generally, an ionic surfactant with a linear C12–C16 alkyl chain has a Krafft point around or above room temperature. Therefore, there is a demand for ionic-surfactant-based WLMs with greater lowtemperature stability. Silicone surfactants have flexible hydrophobic chain structures. Hence, they are expected to be suitable candidates for WLMs that can be stable at low temperatures. Sodium trimethylsilyl tetra(dimethylsiloxane) decyl sulfate (Si〈sub〉5〈/sub〉C〈sub〉10〈/sub〉SO〈sub〉4〈/sub〉Na) and benzyltrimethylammonium chloride (BTAC) were used as surfactant and electrolyte, respectively, to obtain the WLM system with desired properties. No precipitation of surfactant crystals was observed in the WLM system obtained in this study when temperature was decreased to as low as 0 °C, indicating excellent low-temperature stability. Steady rheological measurements on the viscous solutions show shear thinning corresponding nearly to a power law relation (viscosity ∝ [shear rate]〈sup〉−1〈/sup〉). Zero shear viscosity (〈em〉η〈/em〉〈sub〉0〈/sub〉) increased with increase in 〈em〉R〈/em〉, reaching a maximum at around 〈em〉R〈/em〉 = 0.3 and decreasing thereafter. Oscillatory shear measurements for the viscoelastic samples, formed around the maximum-viscosity composition, show that the storage modulus (〈em〉G′〈/em〉) and the loss modulus (〈em〉G′′〈/em〉), with respect to the oscillation frequency (〈em〉ω〈/em〉), cross each other and fit the Maxwell model very well in the low-〈em〉ω〈/em〉 region. The normalized Cole-Cole plot of 〈em〉G′′〈/em〉 / 〈em〉G′′〈/em〉〈sub〉max〈/sub〉 against 〈em〉G′〈/em〉 / 〈em〉G′′〈/em〉〈sub〉max〈/sub〉 was obtained as a semicircle centered at 〈em〉G′〈/em〉 / 〈em〉G′′〈/em〉〈sub〉max〈/sub〉 = 1, as is typical for WLM systems.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719308295-ga1.jpg" width="356" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 20 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Jian Xiao, Honglin Luo, Haiyong Ao, Yuan Huang, Fanglian Yao, Quanchao Zhang, Yizao Wan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Although recombinant human bone morphogenetic protein-2 (rhBMP-2) has been widely applied for bone regeneration, finding an ideal delivery system with optimal dose and minimal side effects is still a challenge. In this context, a novel mesoporous bioactive glass nanotubular (MBG-NT) scaffold loaded with rhBMP-2 was developed using a template-assisted sol-gel method. The obtained MBG-NT scaffold showed a notable 3D network structure and the nanotubes had an outer diameter of approximately 45 nm and a wall thickness of 15 nm. X-ray photoelectron spectroscopy (XPS) certified that the rhBMP-2 was successfully loaded into the MBG-NT scaffold with a quantity of 184.3 〈strong〉±〈/strong〉 5 ng mg〈sup〉-1〈/sup〉, and the MBG-NT scaffold exhibited a sustained release of rhBMP-2 for 28 days due to the presence of mesoporous structures. Moreover, the rhBMP-2-loaded MBG-NT scaffold exhibited enhanced proliferation, alkaline phosphatase (ALP) activity and osteogenic-related gene expression of human bone marrow stromal cells (hBMSCs) when compared to bare MBG-NT scaffold. We believe that the rhBMP-2-loaded MBG-NT scaffold can be a promising scaffold for regeneration of large bone defects.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571930826X-ga1.jpg" width="285" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Razieh Zahedi, Zahra Asadi, Fahimeh Dehghani Firuzabadi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel heterogeneous catalyst was developed via the immobilization of a copper complex by covalent anchoring of the ligand on the surface of magnetic nano particles. The catalyst was characterized by various techniques including Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron micrograph (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), a vibrating sample magnetometer (VSM) and inductively coupled plasma (ICP) spectroscopy. The prepared catalyst demonstrated high catalytic activity, stability, reproducible dispersibility, and recycability in the O-arylation reactions. Moreover, the catalyst could be easily recovered under the outside magnetic field and reused without noticeable decreasing in its catalytic performance upon five consecutive runs.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307162-ga1.jpg" width="271" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Akram Abbasi, Arijit Bose〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The high electrical conductivity of multilayer graphene (MLG) and their sheet like morphology results in a low percolation threshold, and makes it an attractive filler for inducing electrical conductivity in an insulating polymer at small filler loadings. However, strong van der Waals forces between the flat faces of multilayer graphene cause agglomeration, making it difficult to disperse them in a polymer. The loading required for forming a percolating network of these MLGs then increases dramatically, and the advantage of their sheet-like morphology is lost. To enhance the dispersion of MLGs, carbon black nanoparticles (CB) were added as secondary fillers to a polystyrene (PS) matrix containing 2.5 vol% MLG. The electrical conductivity of the composite increased from 10〈sup〉−9〈/sup〉 S/m with no CB to 10〈sup〉-4〈/sup〉 S/m with 1.5 vol% CB, asymptoting to 10〈sup〉3〈/sup〉 S/m at ∼12 vol% CB. Using Raman spectroscopy and wide-angle X-ray diffraction, we confirmed that the CB particles act as dispersion aids and prevent MLG restacking, reducing agglomeration and enhancing dispersion of the MLG sheets in PS. This leads to an increase of several orders of magnitude in electrical conductivity.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307150-ga1.jpg" width="269" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Jiaoyuan Lian, Suxia Zheng, Cong Liu, Zhongbin Xu, Xiaodong Ruan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We propose a co-flowing step emulsification strategy for the on-line control of micro-droplet generation. The effects of four parameters including wall contact angle, plateau length, channel distance and diameter are investigated numerically and experimentally in this study. The results indicate that the wall contact angle, whose applicable range can be expanded to 90°–180° by co-flow, is critical to droplet formation. The effect of the plateau length on droplet generation is reduced by the co-flow, and the droplet diameter is almost independent of the plateau length, which ranges from 0.7 to 1.5 mm. In addition, the droplet diameter increases significantly with increasing channel distance and diameter. Combining these results with those of our previous study, we derived an explicit equation for droplet diameter prediction. The predicted droplet diameter based on this equation has good agreement with the simulation and experimental results. Furthermore, we proposed a coefficient 〈em〉α〈/em〉 as a function of physical and dimensional parameters to predict the regimes and modes in the co-flowing step emulsification process. The conclusion of this study not only provides an important reference for the design and improvement of step emulsification chips, but also offers a new idea and a scientific basis for tuneable monodisperse micro-droplet production.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307216-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Biao Zhang, Xiaojuan Li, Yang Zhao, Hua Song, Huan Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Oxygen doped mesoporous graphitic carbon nitride(O-mpg-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉) was innovatively prepared through facile two-step synthesis and characterized through different characterization tools, such as XRD、SEM、XPS etc. These characterizations confirm that the as-prepared sample has separated plate-like structure with lots of gaps and oxygen atoms have been successfully doped into them. Evaluated by photodegradation of Rhodamine B and Methyl Orange, the O-mpg-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 photocatalyst exhibits higher photocatalytic degradation efficiency, which is attributed to the added active spots, shorter electronic transmission distance and wider range of light absorption. In addition, the photocatalytic activity of the as-prepared catalysts didn’t decrease significantly after five photodegradation cycles, showing a high photocatalytic stability.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Oxygen doped mesoporous g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 was firstly prepared by a facile calcination-solvothermal method and exhibits excellent photocatalytic degradation performance, which is ascribed to the change of morphology and intrinsic electronic structure.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307241-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Wenjie Liu, Kun Yuan, Peipei Liu, Ming Chen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this article, magnetically responsive catalysts were successfully synthesized by host-guest chemistry and self-assembly strategy. Firstly, β-cyclodextrin (β-CD) was bound directly to the surface of core/shell magnetic Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@C (MFC) using chemical bonding methods. Then, in view of the host-guest recognition, p-aminothiophenol (pATP) was captured by β-CD to form inclusion complex on the surface of MFC. Lastly, pre-synthesized gold, silver, platinum nanoparticles (AuNPs, AgNPs, PtNPs) could be adsorbed on the surface of MFC@β-CD-pATP through self-assembly strategy to fabricate ternary composites MFC@β-CD-pATP@metal nanoparticles. Catalytic reduction reaction of methylene blue using NaBH〈sub〉4〈/sub〉 as reducing agent evaluates the catalytic performance of three as-prepared magnetic nanocomposites. MFC@β-CD-pATP@AuNPs catalyst showed the fast catalytic reaction rate constant. Significantly, we have explored the separation of magnetic supports and novel metal nanoparticles under mild conditions. This strategy will become a green and environmental way for highly efficient separation of precious metals catalysts, and recycle and reuse of catalyst carriers.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307174-ga1.jpg" width="362" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Piero De Leonardis, Francesco Cellesi, Nicola Tirelli〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We explored a versatile enzyme nanoencapsulation process based on the synthesis of silica gel nanoparticles, decorated with a dense hydrophilic poly(glycerol monomethacrylate) (PGMMA) shell for biological and therapeutic applications. These hybrid enzyme-SiO〈sub〉2〈/sub〉-polymer nanoparticles were obtained through an aqueous sol-gel process, followed by the adsorption of cationic macroinitiators by electrostatic complexation. Surface-initiated Atom Transfer Radical Polymerisation (ATRP) was applied to obtain a dense hydrophilic (protein repellent) PGMMA layer of tunable size, under conditions which are compatible with the nanoencapsulation of horseradish peroxidase. The sol-gel synthetic procedure, the composition and molecular weight of the macroinitiators, the polymer adsorption and purification methods, and the final ATRP conditions, were optimised to control the properties of these nanoparticles, in terms of particle size, Z-potential, PGMMA decoration, while preserving enzymatic activity.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307228-ga1.jpg" width="489" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈p〉Enzyme-SiO〈sub〉2〈/sub〉-polymer nanoparticle obtained by enzyme (HRP) nanoencapsulation in silica gel nanoparticles, adsorption of a cationic macroinitiator, and final polymer shell generation (PGMMA) by ATRP.〈/p〉 〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): F. Salerni, D. Orsi, E. Santini, L. Liggieri, F. Ravera, L. Cristofolini〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉We employ Diffusing Wave Spectroscopy (DWS) to characterize microscopic structure, internal dynamics and rheological properties of a paradigmatic emulsion formed by water and dodecane stabilized by the anionic surfactant Sodium Dodecyl Sulfate (SDS).〈/p〉 〈p〉We focus on ageing and stability in the regime of low surfactant concentration, well below the Critical Micellar Concentration (CMC). In the long-time ageing regimes differentiate in stable and unstable, depending on surfactant concentration. For the stable case, ageing affects the dynamics following a power law with an exponent independent on surfactant concentration, presumably related to the late stages of the water drainage process. On the contrary, at constant ageing, the dependence of the dynamics from surfactant concentration shows a slowdown, corresponding to a maximum in the bulk shear mechanical modulus, around 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si25.svg"〉〈mo〉[〈/mo〉〈mi〉S〈/mi〉〈mi〉D〈/mi〉〈mi〉S〈/mi〉〈mo〉]〈/mo〉〈mo〉=〈/mo〉〈mn〉2〈/mn〉〈mi〉m〈/mi〉〈mi〉M〈/mi〉〈/math〉 which is reminiscent of a similar maximum found by drop tensiometry in the dilational modulus of the single interface.〈/p〉 〈p〉This suggests a consistent picture of the mechanisms (de)stabilizing the emulsion, explained in terms of elementary process at the interface. These results show furthermore that DWS can be a reliable diagnostic for the study of the aging and of the mechanical properties of concentrate emulsions. This might be relevant to control stability of emulsions when a low concentration of surfactant is desired, e.g. for economical or environment reasons.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719301876-ga1.jpg" width="334" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Huijian Ye, Xuanhe Zhang, Chunfeng Xu, Lixin Xu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The polymer film capacitor has been widely applied in electronics and stationary power system due to the large power density and graceful dielectric reliability. The current requirements for flexible film capacitor are mainly on the development of polymer nanocomposite with high energy density and charge-discharge efficiency during applied electric field. Here we employed the fluoro hyperbranched polyethylene-graft-poly(trifluoroethyl methacrylate) (HBPE-〈em〉g〈/em〉-PTFEMA) copolymer to exfoliate the boron nitride nanosheets (BNNSs) in low-boiling-point solvent, and then, the flexible poly(vinylidene fluoride-trifluoroethylene) (P(VDF-CTFE)) nanocomposite film incorporated with BNNSs was prepared by the simple solution casting. The stable BNNSs dispersion was obtained with assistance of fluoro hyperbranched copolymer as the stabilizer, which was adsorbed on the nanosheets via the noncovalent CH-π interaction against aggregation. The presence of fluoro segments improves the compatibility of BNNSs/P(VDF-CTFE) nanocomposite, which contributes to the large interfacial polarization. The energy density in 0.4 wt% nanocomposite achieves 6.8 J/cm〈sup〉3〈/sup〉 with charge-discharge efficiency of 66% at 300 MV/m, which is ascribed to the large content of electroactive phase and the enhanced interfacial polarization. The fluoro hyperbranched copolymer functionalized BNNSs/P(VDF-CTFE) nanocomposite film exhibits high electric storage capability as well as lightweight feature and flexibility, which is benefit to potential applications for portable and implantable electrical devices where both the weight and size are primary concerns.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571930723X-ga1.jpg" width="287" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): Mohammad M. Hassan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, multifunctional wool fabrics were produced by treating them with silver (Ag) nanoparticles in a single-stage treatment using trisodium citrate (TSC) as a reducing and capping agent. The effects of treatment parameters, such as Ag〈sup〉+〈/sup〉 concentration, pH, temperature and time on the colour strength, antibacterial and antistatic properties, and UV radiation absorption by the treated fabric were carried out. It was found that the wool fabric treated with Ag nanoparticles formed by using Ag〈sup〉+〈/sup〉 concentration of less than 1.11% on the weight of wool fibres produced very pale shade. The colour strength and UV radiation absorption capacity of the treated wool fibres increased with an increase in the concentration of Ag〈sup〉+〈/sup〉, and Ag〈sup〉+〈/sup〉 to citrate anion ratio, and also with a decrease in the treatment pH. The treatment temperature had a great effect on the colour strength of the treated fabrics and the size of Ag nanoparticles. The colour strength increased from 1.59 for the fabric treated at 55 °C to 7.74 for the fabric treated at 95 °C. The surface resistance of the treated wool fibres decreased with an increase in the concentration of Ag〈sup〉+〈/sup〉, while the colour fastness to washing decreased for the fabric treated at a higher pH. The treated fibres showed excellent antibacterial activity, UV radiation absorption capacity, and also very good antistatic properties along with an excellent colourfastness to washing. Moreover, the developed treatment is highly durable to washing as after 20 washes the treated fibres lost their colour and antibacterial activity only marginally.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719308076-ga1.jpg" width="415" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 17 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Yixing Wang, Taijun He, Mengyun Liu, Jianqi Ji, Yu Dai, Yang Liu, Longbo Luo, Xiangyang Liu, Jiaqiang Qin〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Fast and efficient oil-water separation materials under harsh conditions become urgent requirement for eliminating destruction of environment from offshore oil spill, oily wastewater produced in industry and life. Here, we designed and prepared polyimide (PI) aerogel with strong hydrogen bond by introducing benzimidazole structure. The hydrogen bond increases the intermolecular interactions to overcome the expansion force and capillary force during ice crystal growth and sublimation. The obtained PI aerogel has a mutually interleaved sheet three-dimensional network structure of thin pore walls (about 85 nm), interconnected pores and tortuous channels with a low shrinkage (about 7.8%). Moreover, due to the high hydrophobicity and morphological characteristics, the PI aerogel can be used for oil-water separation continuously under different harsh conditions, such as high viscosity oil (above 570 mPa·s), oil in cold/hot water (0 °C/120 °C), corrosive solution and emulsion. The separation efficiency and maximum oil flux can reach 99. 9% and 14320 L·m〈sup〉-2〈/sup〉 h〈sup〉-1〈/sup〉, respectively. Because of their fast and efficient oil-water separation performance in harsh environments, this PI aerogel shows great potential in the field of petroleum, municipal and industrial wastewater treatment.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307976-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 13 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Junmei Tian, Zhijia Zhu, Baojiang Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Photocatalysts with heterojunctions had attracted much attention in the field of photocatalysis due to their strong charge separation and transfer capabilities. In this work, a novel Bi〈sub〉2〈/sub〉MoO〈sub〉6〈/sub〉/Bi〈sub〉2〈/sub〉WO〈sub〉6〈/sub〉/MWCNTs Z-scheme photocatalyst was firstly prepared by one-step hydrothermal method. A series of characterization results showed that the ternary flower-like Bi〈sub〉2〈/sub〉MoO〈sub〉6〈/sub〉/Bi〈sub〉2〈/sub〉WO〈sub〉6〈/sub〉/MWCNTs photocatalyst was successfully synthesized. The photocatalytic property of Bi〈sub〉2〈/sub〉MoO〈sub〉6〈/sub〉/Bi〈sub〉2〈/sub〉WO〈sub〉6〈/sub〉/MWCNTs composite was evaluated by photo-degradation of reactive blue 19 (RB-19) dye under visible light irradiation. The results manifested that Bi〈sub〉2〈/sub〉MoO〈sub〉6〈/sub〉/Bi〈sub〉2〈/sub〉WO〈sub〉6〈/sub〉/MWCNTs composite presented the better photocatalytic property than pure Bi〈sub〉2〈/sub〉WO〈sub〉6〈/sub〉 and Bi〈sub〉2〈/sub〉MoO〈sub〉6〈/sub〉/Bi〈sub〉2〈/sub〉WO〈sub〉6〈/sub〉. Additionally, in the photocatalytic process free radical and hole scavenging experiments indicated that h〈sup〉+〈/sup〉 and ·O〈sub〉2〈/sub〉- played an indispensable role. Finally, possible mechanisms for the photocatalytic enhancement of the composite were put forward.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307861-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): Chao Zhang, Siyao Liu, Shuangxi Li, Yue Tao, Panpan Wang, Xinyue Ma, Lanzhou Chen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The magnetic chitosan microspheres immobilized 〈em〉Aspergillus sydowii〈/em〉 (MCMAs) was prepared and characterized by SEM, BET, XRD and VSM analyses, and used to adsorb Cu(II) from aqueous solution under different influence factors such as contact time, initial Cu(II) concentration and biosorbent dose. Characterization results showed that MCMAs had large specific surface area and were rapidly separated from aqueous solution by using an adscititious magnetic field. Batch adsorption experiments showed that Cu(II) adsorption capacity of MCMAs was up to 119.21 mg g〈sup〉−l under the optimal condition. The CO, OH and NH〈/sup〉〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉 groups played an important role in Cu(II) chelation observed from FTIR spectra. Cu(II) adsorption onto MCMAs was well described by pseudo-second-order kinetics and Langmuir isotherm, and the adsorption process involved surface and intra-particle diffusion. In addition, MCMAs showed good recyclable efficiency after four adsorption-desorption cycles.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719308015-ga1.jpg" width="334" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): Suvendu Manna, Snigdha Prakash, Papita Das〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This article presents the process of synthesizing a value added product from a carbonaceous industrial waste. For this a carbonaceous industrial waste was coated with graphene oxide (GO) and then thermally activated at 800 °C. The GO and the GO-coated biochar were characterized with atomic force microscope, raman spectroscope, fourier transform infrared spectroscopy, field-emission scanning electron microscope, x-ray Diffraction and transmission electron microscope. This GO-coated biochar was then utilized to investigate removal capacity of phenol present in wastewater. The data indicated that the GO-coated biochar showed better phenol removal efficacy then that of the GO itself. The isotherm analysis indicated that the data could be described best with Langmuir isotherm indicating that the phenol separation was a monolayer surface adsorption. The kinetic analysis indicated that the phenol separation process was followed by pseudo second order kinetics. Also, it was evident from the intra-particle diffusion kinetic analysis that diffusion plays a significant role in phenol separation. From thermodynamic analysis it was evident that the phenol separation process was endothermic as well as spontaneous in nature. The GO-coated biochar showed better separation efficacy in the presence of salt.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719308064-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Yong-li Yan, Qi Xi, Christian-chibuike Una, Bing-cheng He, Chun-sheng Wu, Long-long Dou〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The serious fingering and nonuniform injectivity profile of acid liquid result from the features of heterogeneity in most carbonate reservoir, leading to a poor effect on the acidizing process. In the present contribution, for the first time, we report a novel diversion acidizing strategy that uses acid-rock reaction between the acidizing fluid itself and carbonate core to produce CO〈sub〉2〈/sub〉 at supercritical state. Under the action of a mixture of foaming agent and stabilizer contained in this working fluid, a CO〈sub〉2〈/sub〉 foamed acid fluid is in-situ formed in the acidizing layer, which would play a diverting role in carbonate matrix acidizing operations. Experiments on in-situ formation of CO〈sub〉2〈/sub〉 microfoams (emulsions) were performed utilizing a visible acid-rock reaction simulation device and a self-made high pressure and temperature foam generator. A series of divided-flow experiments were undertaken by the core displacement setup.〈/p〉 〈p〉Results based on these experiments indicate that with 0.5% SDBS as a foaming agent and 0.15% CMC as a stabilizing agent, the supercritical CO〈sub〉2〈/sub〉 microfoams (emulsions) could be created in-situ in the process of acidizing through the carbonate reservoirs. The foamed acid has the accumulating and plugging effects, with divided-flow selectivity not only in the parallel cores of oil saturation and water saturation, but also in the parallel cores of different permeability. This foamed acid fluid could provide better diversion acidizing operations for heterogeneous carbonate formation. Finally, the mechanism of this novel diversion acidizing technology was uncovered in detail. It is suggested that the whole working process is actually an interface effect in the dynamic system of gas/liquid/solid multiphase fluid. Such findings are potentially important for a better understanding on the mechanisms of in-situ formation of CO〈sub〉2〈/sub〉 foamed acid and its self-diversion. Looking out to the future, our report attempts to provide a new and efficient technology for the improvement of acid stimulation in the carbonate reservoirs.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉A novel diversion acidizing technology using in-situ microfoams to meet the challenge of serious fingering and poor backflow of acid liquid existing in application of diverting acid technology in heterogeneous formations. This technology uses a chemical reaction between conventional acid and carbonate cores to produce CO〈sub〉2〈/sub〉 at supercritical state. Under the action of a mixture of foaming agent and stabilizer, a CO〈sub〉2〈/sub〉 foam fluid was in-situ formed, which would play a diverting role in carbonate matrix acidizing operations. It is suggested that the whole working process is actually an interface effect in the dynamic system of gas/liquid/solid multiphase fluid.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307757-ga1.jpg" width="200" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): Tao Ma, Haishun Feng, Hairong Wu, Zhe Li, Jiatong Jiang, Derong Xu, Ziyu Meng, Wanli Kang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Gemini surfactant has a good application prospect in the field of enhanced oil recovery (EOR) due to the advantages of high interfacial activity, low critical micelle concentration (CMC) and good wettability alteration. In this paper, ethylenediamine, sodium 2-bromoethanesulphonate and fatty alcohol polyoxyethylene ether are used as raw materials to synthesize a new kind of anionic-nonionic gemini surfactant which hydrophilic group consists of two parts nonionic and anionic groups through a mild reaction of amination. The surface tension, interfacial tension, wettability and oil displacement of the synthesized anionic-nonionic gemini surfactants were evaluated. Parameters of surfactant the saturated adsorption amount 〈em〉Γ〈/em〉〈sub〉max〈/sub〉 and the minimum molecular occupied area 〈em〉A〈/em〉〈sub〉min〈/sub〉 were calculated. The structures of the optimal product were characterized by IR and 〈sup〉1〈/sup〉H-NMR. The results showed that the critical surface tension of the synthesized anionic-nonionic gemini surfactant was as low as 28.94 mN/m, and the critical micelle concentration was 4.9 × 10〈sup〉−5〈/sup〉 mol/L. An interfacial tension between the aqueous solution of 600 mg/L optimal surfactant and Dagang crude oil was 0.0804 mN/m. 1500 mg/L aqueous solution can reduce the surface contact angle of lipophilic low permeability core from 144.5° to 71.5°. The anionic-nonionic gemini surfactant (1000 mg/L; 0.4 PV) can improve oil displacement efficiency by 7.03%. The current study opens a new pathway for designing enhancing oil recovery applicable gemini surfactants with excellent performance, wide source of raw materials and low dosage.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307885-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): Zengzi Wang, Runtao Hu, Gaihuan Ren, Gongrang Li, Shangying Liu, Zhenghe Xu, Dejun Sun〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The application of conventional alkalis (NaOH or Na〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉) in alkali/surfactant/polymer (ASP) flooding is rather limited due to their intrinsic drawbacks, including precipitating during injection into formation water with a high divalent ion concentration and enhancing the dispersibility of clays (e.g., montmorillonite (MMT) or kaolinite) in water, which lead to damage to reservoir formations and bring about difficulties in treating produced fluids. Here, we propose polyetheramine D 230 as an alternative alkali to avoid these problems. D 230 is a diamine linked by poly(oxypropylene) backbones. Interfacial tension and emulsification measurements proved that D 230 can neutralize the acidic components in crude oil to generate surface-active soaps, which facilitate oil emulsification in water. Contact angle measurements indicated that an oil-contaminated quartz surface treated with D 230/SP blends was successfully altered from oil-wet to water-wet. Sand pack flooding measurements demonstrated that a D 230/SP injection was able to mobilize 19.23% of the original oil in place (OOIP) after thorough water flooding. Rheograms of alkali/polymer blends showed a reduced impact of D 230 on viscosity. Static bottle tests indicated that no precipitation occurred after D 230 was injected into formation water with a high Ca〈sup〉2+〈/sup〉 concentration. Colloidal stability measurements of clay dispersions suggested that D 230 can inhibit clay dispersibility. As an alternative alkali in ASP flooding, D 230 not only facilitates enhanced oil recovery (EOR) but also solves problems such as precipitation, high biotoxicity, reduced fluid viscosity and enhanced clay dispersibility brought about by conventional inorganic and organic alkalis. These advantages make D 230 an eco-friendly choice as an alkali for ASP flooding.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719308088-ga1.jpg" width="362" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): Mohsin Ali Marwat, Bing Xie, Yiwei Zhu, Pengyuan Fan, Kai Liu, Meng Shen, Malik Ashtar, Suwadee Kongparakul, Chanatip Samart, Haibo Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The sandwich-structured barium titanate/poly(ether imide) (BT/PEI) nanocomposites are fabricated layer-by-layer, with outer two insulation layers (ILs) for high breakdown strength and a middle polarization layer (PL) for high dielectric constant, using solution casting technique. Consequently, the sandwich-structured BT/PEI nanocomposites with optimum BT NPs concentration in ILs and PL showed tremendously enhanced discharge energy density (〈em〉U〈/em〉〈sub〉e〈/sub〉) of 5.7 J/cm〈sup〉3〈/sup〉, which is ∼256% and ∼307% higher than the pristine PEI (with 1.6 J/cm〈sup〉3〈/sup〉) and its single-layered counterpart, i.e., 9 wt.% BT/PEI (with 1.4 J/cm〈sup〉3〈/sup〉), respectively. The similar sandwich structure also displayed a significantly higher discharge efficiency of ∼62% at very high electric field. In addition, the high-temperature hysteresis loops for optimal sandwich structure nanocomposites revealed considerably high-temperature endurance until 150 °C at 200 MV/m. The present work paves the way for using sandwich-structured linear nanocomposites in thermally stable energy storage devices.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307903-ga1.jpg" width="267" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): Sabrina Matos de Carvalho, Carolina Montanheiro Noronha, Cleonice Gonçalves da Rosa, William Gustavo Sganzerla, Ismael Casagrande Bellettini, Michael Ramos Nunes, Fabiano Cleber Bertoldi, Pedro Luiz Manique Barreto〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Natural antioxidants can be incorporated into polymers to the production of active packaging, preventing the formation of off-flavors and undesirable textures in foods, increasing the foods shelf life. In this study was developed polymeric films based on poly (vinyl alcohol) (PVA) incorporated with 30, 50 and 70% of solid lipid nanoparticles entrapped α-tocopherol. PVA films were produced by the casting technique and characterized by their physicochemical, morphological, thermal and antioxidant characteristics. PVA films with nanoparticles demonstrated higher hydrophilic compared to the control film. Thermal analysis of the films showed that nanoparticles incorporation has changed the structure, decreasing the crystallinity. Moreover, films with solid lipid nanoparticles entrapped α-tocopherol demonstrated a higher antioxidant capacity, and the α-tocopherol controlled release confirmed the possibility of its use as active packaging to application in food conservation.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307812-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 19 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Yudai Chizawa, Yayoi Miyagawa, Mao Yoshida, Shuji Adachi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mayonnaise is a preferred dressing that is routinely used in many regions. Distribution of products containing frozen mayonnaise is highly desirable due to the development of cold chain and changing lifestyle. However, freezing and thawing of mayonnaise result into separate oil and aqueous phases. A detailed mechanism of this phenomenon is still unknown. In this study, the destabilization of frozen emulsions, using rapeseed, safflower, olive, rice bran, and soybean oils as the oil phase was examined, in which these oil phases crystallize at lower temperature than the aqueous one. The vegetable oils exhibit different crystallization behavior. Irrespective of the type of vegetable oil, it was found that smaller the difference between the storage temperature and the melting point of the oil, which was estimated from the fatty acid composition, quicker was the destabilization of the emulsion prior to the growth of the oil crystal. We consider that the change in the crystallization process of the oil phase increases the energy at the oil–water interface and destabilizes the emulsion.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571930812X-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Pablo Llombart, Mauricio Alcolea Palafox, Luis G. MacDowell, Eva G. Noya〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Controlled CTAB self-assembly is an essential prerequisite for the formation of gold nanorods with tailored shape and monodispersity. In this paper, we exploit the use of salt concentration and co-surfactant decanol for the preparation of CTAB aggregates with different morphologies. To this end we use a model of CTAB recently developed by ourselves, and perform electronic structure calculations in order to improve current point charge parametrization of decanol. Using molecular dynamics simulations with the new models, we find a sequence of structural transitions of CTAB aggregates induced by salt concentration and added cosurfactant. In pure solutions, CTAB aggregates form spherical micelles with a compact ionic shell and a diffuse double layer that can be qualitatively described with Poisson–Boltzmann theory. Addition of decanol as a cosurfactant induces a sequence of dramatic structural transitions at low surfactant concentration and allows the stabilization of compact ordered bilayers in a well defined range of intermediate decanol/CTAB ratios. At low and high decanol/CTAB ratios spherical micelles are transformed into wormlike cylindrical micelles. At intermediate decanol/CTAB ratios, fully formed bilayers are observed, with surfactants exhibiting a compact structure with strong positional and orientational order. We discuss how the controlled self-assembly of compact CTAB bilayers at low global CTAB concentration can pave the way for the selective passivation of gold facets and the controlled formation of monodisperse gold nanorods.〈/p〉〈/div〉 〈div〉 〈h6〉Graphical abstract〈/h6〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307186-ga1.jpg" width="275" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Tülin Gürkan Polat, Kayhan Ateş, Süleyman Bilgin, Osman Duman, Şükrü Özen, Sibel Tunç〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, gelatin-based conductive hydrogels doped with carbon nanotube (CNT), poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and silver (Ag) nanoparticle were prepared for use in biopotential measurements. Gelatin was modified by various concentrations of methacrylic anhydride (MA) to obtain photo-crosslinkable gelatin methacrylate (GelMA) polymer with low (21%), medium (44%) and high (78%) methacrylation degree. Chemical modification of gelatin was characterized by 〈sup〉1〈/sup〉H-NMR spectroscopy. It was observed that mechanical properties of the GelMA hydrogels were highly dependent on methacrylation degree. Ultimate compressive stress of low, medium and high methacrylated gelatin hydrogel was measured to be 9.97 ± 0.14 kPa, 17.83 ± 1.73 kPa and 38.23 ± 2.96 kPa, respectively. Surface morphology of hydrogels was visualized by scanning electron microscope (SEM). The pore size of methacrylated gelatin hydrogel significantly reduced with the addition of CNT, PEDOT:PSS and Ag nanoparticle into the hydrogel matrix. The results of thermal gravimetric analysis showed that conductive hydrogels were of higher thermal stability than nonconductive GelMA hydrogel. The suitability of the prepared hydrogels for biopotential measurements was determined by equivalent impedance measurements. Impedance values of hydrogel samples were obtained in the frequency range of 20 Hz–500 Hz. The hydrogel materials prepared in this study exhibited high impedance at low frequencies and low impedance at high frequencies. The results of this study showed that the hydrogels produced with Ag nanoparticle are more suitable electrode materials for physiological measurement systems such as electrocardiography (ECG) and electroencephalography (EEG).〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307393-ga1.jpg" width="438" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Siddhesh Kamat, Runxing Lin, Yee C. Chiew〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Reduction of interfacial tension caused by surfactants at oil/water interfaces plays a crucial role in many technological processes and industrial applications such as detergency, food processing, cosmetics and personal care, wastewater treatment, pharmaceutical and oil industries. The properties and behavior of dispersions, foams, and emulsions are determined by the interfacial properties stabilized by the surfactants. We carried out molecular dynamics simulations to study the interfacial properties, structure and dynamics of dodecanedioic dicarboxylic acids at hexane/water interface over a wide range of surface coverage (area per molecule). Unlike monocarboxylic acid whose hydrocarbon tail points to the oil phase normal to the oil/water interface, the two carboxyl groups of the dicarboxylic acid are attached to the aqueous phase while its slightly curved carbon backbone lies parallel to the interface. The dodecanedioic dicarboxylic acid adopts a slightly curved linear conformation in the interfacial region. The adsorbed acids undergo a first-order gas-to-liquid phase transition as the density of acid increases. The characteristic thickness of the acid layer remains practically constant at large area per molecule (or, low surface density) until surface coverage reaches a “critical” value above which the thickness of the acid layer increases markedly deviating from its low density value. This layering transition has a significant influence on the spreading pressure, interfacial structure, and lateral diffusion coefficient of the acids. Additionally, we modeled a system of fully deprotonated negatively charged acids balanced by positively charged sodium counterions. We found that the interfacial tension of the charged acid interface is consistently lower than uncharged acid at moderate to higher surface density; however, at low densities, we observe little difference in interfacial tension between these two systems within the accuracy of the MD results. Additionally, we found that the rotational relaxation of the charged acids is significantly slower than that of uncharged acids owing to strong electrostatic interactions between the carboxyl groups COO〈sup〉−〈/sup〉and sodium Na〈sup〉+〈/sup〉cations which restrain the rotational motion of the acid. This molecular dynamics study has provided information and insights at the molecular level on the structure, equilibrium, and dynamic properties of dicarboxylic dodecanedioic acids at hexane/water interface.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307137-ga1.jpg" width="494" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Xinyu Zheng, Huaili Zheng, Yuhao Zhou, Yongjun Sun, Rui Zhao, Yongzhi Liu, Shixin Zhang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Wastewater containing dyes poses a severe threat to human health and to environmental safety. Hence, finding an effective way to treat this wastewater has attracted wide attentions. In this study, quaternary ammonium group-rich magnetic nanoparticles (MNPs), Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@SiO〈sub〉2〈/sub〉-MPS-g-DAC (FSMD), were facilely prepared by grafting polymerization and served as a cationic adsorbent to remove anionic dye Orange G from aqueous solutions. Being compared with Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉@SiO〈sub〉2〈/sub〉-MPS MNPs, the adsorption capacity of FSMD MNPs was notably enhanced and it could be maintained in a high level under a wide solution pH range. The dependency on pH and the sensitivity to ionic strength indicated that the main adsorption mechanism was the electrostatic interaction. The adsorption kinetics followed the pseudo-second-order model, and the adsorption isotherms were well described with the Langmuir model. According to the thermodynamic analysis, the adsorption process was spontaneous and endothermic. FSMD MNPs were proved to have advantages of fast adsorption rate, high adsorption capacity, easy separation ability under external magnetic field, and satisfactory reusability, therefore they can be applied in the removal of anionic dyes from wastewater.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307344-ga1.jpg" width="370" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Du Ren, Yujie Chen, Hua Li, Hafeez Ur Rehman, Yunli Cai, Hezhou Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Shape memory assisted self-healing polymeric networks have been numerously explored due to their multi-functionality and sustainability. In this study, we prepare a kind of electrical and thermal dual-responsive shape memory assisted self-healing polymeric composites fabricated with polycaprolactone/thermoplastic polyurethane (PCL/TPU) and carbon nanotubes (CNTs) via a facile method. The CNTs/PCL/TPU composites use PCL/TPU blend as shape memory polymer matrix, PCL as healing agent and CNTs as reinforcement networks. CNTs greatly enhance mechanical strength of the composites with good electrical and thermal conductivity. Interestingly, the CNTs/PCL/TPU composites can be healed via electricity and heating respectively in tens of seconds with corresponding optimal healing efficiencies about 96% and 94%. Meanwhile, the composites can exhibit remarkable electro-active shape recovery property that assist to diminish the crack openings and then the healing agent would be molten to fill in the crack. Therefore, the proposed materials can offer great potential applications in biomedical, aerospace and microelectronics.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307198-ga1.jpg" width="343" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): J. Carneiro, J.B.L.M. Campos, J.M. Miranda〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study reports the generation and characterization of polydimethylsiloxane (PDMS) microparticles. Droplets are produced in the jetting regime by hydrodynamic flow focusing technique in a PDMS square-section microchannel and afterwards thermally cured. Both the droplets and microparticles size distributions are characterized and compared. During the curing process, there is no appreciable shrinking of the droplets/microparticles. Droplets are generated with a maximum frequency of 1.3 kHz and their diameter ranges from 27 to 59 μm depending on the flow rate ratio. After the cure, the microparticles are chemically and optically characterized. The results show that the droplet generation method and the curing process are able to produce PDMS microparticles with low size, low dispersity and optimal optical properties for visualization and velocimetry experiments.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307253-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Li Duan, ChenChen Qin, Anhe Wang, Shengtao Wang, Jieling Li, Shuo Bai〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, uniform and porous gelatin microgels with various functional nano-objects (platinum nanoparticles and magnetic nanoparticles) were prepared by a ‘casting’ strategy in a controllable manner. During the microgels fabrication, two kinds of nanoparticles can be simultaneously introduced into the microgels without mutual influence, endowing the microgels with the combined functionality of nano-objects. Experimental data showed that the microgels with various nano-objects are stable enough in strong base or acidic solution, and can be taken as an efficient catalysis system and conveniently separated from the reaction medium by magnetic field. The method proposed here is certified to be facile, efficient and low cost to fabricate stable multifunctional microgels.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307472-ga1.jpg" width="259" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Yaya Ma, Cuiqing Zhang, Chengyu Li, Feng Qin, Lin Wei, Changyuan Hu, Quanhong Hu, Shuwang Duo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bi〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 is a newly found semiconductor photocatalyst with visible-light response property; however, due to its large particle size, the photocatalytic efficiency is greatly limited. Reducing the particle size down to nanoscale is an efficient way to enhance the photocatalytic ability, but still challenging. Herein, the firework-shaped hierarchical TiO〈sub〉2〈/sub〉 microsphere was used as the framework to spatially confine the growth of Bi〈sub〉2〈/sub〉O〈sub〉4〈/sub〉. SEM characterization results reveal nanosized Bi〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 particles are successfully inserted into the TiO〈sub〉2〈/sub〉 microsphere, forming enormous Bi〈sub〉2〈/sub〉O〈sub〉4〈/sub〉/TiO〈sub〉2〈/sub〉 heterojunctions. Benefitted from the nanoscaled Bi〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 and the formation of Bi〈sub〉2〈/sub〉O〈sub〉4〈/sub〉/TiO〈sub〉2〈/sub〉 type II heterojunction, both the separation efficiency of charge carriers and the quantum yield are improved. As a result, Bi〈sub〉2〈/sub〉O〈sub〉4〈/sub〉/TiO〈sub〉2〈/sub〉 heterojunctions show much higher photocatalytic activity than that of pristine Bi〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 in the degradation of methyl orange and tetracycline under visible light. Radical capture experimental results imply that hole is the dominant reactive species for the degradation of methyl orange. The present work paves the way for designing nanosized photocatalyst via the space-confined effect.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉A space-confined strategy is developed to restrict the size of Bi〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 down to nanoscale level and as-constructed Bi〈sub〉2〈/sub〉O〈sub〉4〈/sub〉/TiO〈sub〉2〈/sub〉 heterojunctions display superior photocatalytic performance than pure Bi〈sub〉2〈/sub〉O〈sub〉4〈/sub〉.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307459-ga1.jpg" width="283" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): A.M. Hezma, A. Rajeh, Mohammed A. Mannaa〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Zinc oxide nanoparticles were prepared by a sol-gel method and characterized by XRD, SEM, TEM and EDX. A series of chitosan and polyvinyl alcohol (Cs/PVA) blend films doped with various concentrations of Zinc oxide nanoparticles (ZnO NPs) were prepared by solution casting method. These samples were characterized by various analytical techniques. XRD patterns of the prepared samples showed increasing in amorphousity of the polymer blend with increasing the content of ZnO NPs in Cs/PVA blend. The FT-IR analysis confirmed the complexation between Cs/PVA blend and ZnO NPs. From the UV–vis results, the optical energy gap was calculated. The TGA analysis displayed that the thermal stability of all the samples improved after the addition of the ZnO NPs. By the tensile universal testing machine, the mechanical properties of the prepared films were determined. The antimicrobial analysis showed that all nanocomposite films exhibited enhanced antimicrobial efficacy as compared to pure Cs/PVA film and it is linearly related to the amount of ZnO nanoparticles in the matrix. The sample containing 10 and 15 wt.% ZnO NPs exhibited the highest thermal stability, mechanical strength, and antibacterial activity. This nanocomposite with excellent thermal stability, tensile and antibacterial properties can be potentially utilized for antimicrobial packaging purposes and can be widely used in medical applications.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571930809X-ga1.jpg" width="256" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): Ya Di, Kunling Lu, Yaling Tian, Yan Liu, Yunwang Zhao, Yue Zheng〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Two-phase synthesis is an advantageous alternative to the traditional synthetic method, due to its less toxicity, controllable, mild synthetic conditions and easy large-scale synthesis. However, meeting novel synthesis, the conventional trial-and-error approach could not provide a clear understanding. We herein report synthesis and mechanism investigation of CdS quantum dots in octadecene/glycerol two-phase system. The effects of different reaction parameters and conditions including reaction temperature, reaction time, reactant concentrations, and synthesis routes (one-step and two-step approach) on both nucleation and particle growth were investigated. It was found that the synthesis course was a growth dominated process depending on both CdS(monomer) and CdS(nuclei), and controlled by the interface of ODE/glycerol. The present work provided a new and clear understanding about two-phase system synthesis on semiconductor quantum dots, noble metal nanocrystals and some alloy nanomaterials.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719308003-ga1.jpg" width="377" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Huey-Shan Hung, Da-Tian Bau, Chun-An Yeh, Mei-Lang Kung〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉〈strong〉Gold〈/strong〉nanoparticles (AuNPs) have well applied in imaging and carriers of drugs and/or biomolecules for diseases and cancers therapeutics, due to their tunable physicochemical properties, easy functionalized with biomolecules and biocompatibility. AuNPs conjugated with biopolymer such as collagen has been demonstrated that increased the cell proliferation, migration and cell differentiation. Avemar (Ave) is a nutraceutical from natural components and dietary supplement for healthcare of tumor related anorexia/cachexia. Moreover, Ave has revealed the excellent bio-efficacy of anti-proliferation, cell cycle disturbing and apoptosis induction in numerous types of tumor cells in 〈em〉in vivo〈/em〉 and 〈em〉in vitro〈/em〉. However, the effects of Ave on cellular uptake mechanisms still unclear. In this study, we fabricate the Ave-deposited AuNP-collagen nanocarrier (AuNP-Col-Ave) and investigate their endocytic mechanisms in transformed SCC oral cancer cells and non-transformed BAEC and HSF cell lines. By using DLS assay, Ave-deposited AuNP-Col have shown a particle size of 303 ± 35.2 nm. Both UV–vis absorption assay and FTIR spectrum analysis were also demonstrated that the Ave conjugated onto AuNP-Col. Further, both MTT assay and Calcein AM assay were revealed that AuNP-Col-Ave induced a significant cytotoxicity in cancerous SCC cells and showed nontoxicity and biocompatibility for non-transformed BAEC and HFS cells. In addition, AuNP-Col-Ave has showed an excellent uptake capacity in all these cell lines as compared to AuNP-Col group. Further uptake mechanisms analysis demonstrated that the macropinocytosis seems to be the favorite endocytic mechanism during AuNP-Col-Ave internalized into these transformed and non-transformed cell lines. Altogether, this study is first validating the endocytic mechanisms of AuNP-Col-Ave in transformed and non-transformed cell lines. Our findings will provide a novel insight for endocytic mechanisms of cellular uptake nutraceuticals during nutrition therapy and cancer prevention.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Schematic diagram illustrated that AuNP-Col-Ave-mediated cellular uptake mechanisms and cell fates in both transform and non-transformed cell lines.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307794-ga1.jpg" width="217" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Allan Gomez-Flores, Scott A. Bradford, Lei Wu, Hyunjung Kim〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Particles of various shapes (e.g., spheres or rods), sizes (e.g., nm to microns), interiors (e.g., solid or hollow), and materials are used in many industrial and environmental applications. The Derjaguin–Landau–Verwey–Overbeek (DLVO) theory has commonly been used to calculate and predict the adhesive interaction of these particles with solid surfaces. However, DLVO theory treats these particles as equivalent spheres for simplicity ignoring shape in numerous cases. The surface element integration (SEI) approach allows DLVO theory to be extended for different particle shapes, orientations, and interiors. In this study, the SEI approach was applied to calculate the interaction energy between hollow and solid cylinders with a flat surface. The effect of aspect ratio and particle orientation on interaction energies was investigated under different solution chemistry conditions. Our study is relevant for an extensive range of particle aspect ratios, ranging from nanosized particles such as carbon nanotubes or nanowires, which have high aspect ratios, to micron-sized particles such as bacteria, which have low aspect ratios. The energy barrier tended to increase when the angle that the larger axis of the particle made with the normal to the surface changed from perpendicular (0 rad) to parallel (π/2 rad). The aspect ratio did not affect the trend of the energy barrier for solid (200–1000) and hollow (25–1000) cylinders of relatively high aspect ratios, but it produces a non-monotonic trend for solid (2–100) and hollow (2–10) cylinders of low aspect ratios. The present study advances our understanding of adhesive interactions for particles having a wide range of aspect ratios and interior properties at various orientations with the surface.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307691-ga1.jpg" width="310" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Xiaoqin Huang, Yanli Niu, Zeping Peng, Weihua Hu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Core–shell structured BiOCl@polydopamine (BiOCl@PDA) hierarchical hollow microspheres were synthesized as an efficient photocatalyst towards degradation of pollutants under visible light. As-prepared BiOCl@PDA features hierarchical hollow microsphere structure formed by aggregated BiOCl nanosheets with PDA thin film coated on their surface. It exhibits excellent photocatalytic activity and recycling durability for photodegradation of pollutants under visible light illumination. Detail investigation suggests that the introduction of PDA significantly improves the specific surface areas and enhances the light absorption and interfacial separation, together to improve the photocatalytic efficiency. This work may provide a valuable strategy for the synthesis of highly efficient photocatalysts.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307356-ga1.jpg" width="222" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Sanaz Ghiasi, Ali Behboudi, Toraj Mohammadi, Samaneh Khanlari〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, negatively charged Polyethersulfone (PES)/Polyimide (PI) ultrafiltration membranes were fabricated in order to enhance membrane performance. Moreover, the surface properties such as surface charge and roughness were studied as essential properties which can enhance Polyethyleneimine (PEI) nanofiltration layer assembly. Due to the possibility and observation of phase segregation, for the first time, PES/PI blend was investigated and approved both thermodynamically and experimentally via DSC and FESEM analysis. Highly charged surface of fabricated ultrafiltration (UF) blend membranes were able to reject BSA more than 95% due to smaller pores, surface roughness, and electrostatic forces according to the AFM and zeta potential analyses. Fouling parameters depicted lower fouling with increasing the PI content. Further investigations provided evidence that the presence of PI greatly affected membrane morphology, phase separation behavior, and pore size distribution. According to zeta potential and AFM analysis, the presence of negative charge along with increased roughness of blend membrane surface drastically enhanced the formation of positively charged hyperbranched polyethyleneimine NF layer. As seen in FESEM images, using the blend membranes as substrate enhanced the NF layer assembly by increasing the interfacial affinity resulting in more efficient layer assembly of the NF layer. The NF membranes exhibited high flux (52 LMH/bar) at low pressure (2 bar) in salt removal filtration tests along with increased performance in salts rejection in order of MgSO〈sub〉4〈/sub〉 (72%) 〉MgCl〈sub〉2〈/sub〉 (62%) ≥NaCl (61.4%).〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307411-ga1.jpg" width="242" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Paola Fincheira, Olga Rubilar, Javier Espinoza, Washington Aniñir, Loreto Méndez, Amedea B. Seabra, Andrés Quiroz〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Oil-in-water (O/W) multilayer emulsions have been used to encapsulate volatile organic compounds (VOCs). Nevertheless, research associated with application in horticulture has been poorly studied. The objective of this study was to develop O/W emulsions for releasing VOCs to induce vegetable growth. Emulsions were prepared with vegetable oil, soybean lecithin and polysaccharides to formulate a stable product. The results indicated that O/W emulsions formulated with chitosan and sodium alginate were stable in a wide range of pH, temperature, and ionic strength. Furthermore, a direct relation between emulsions stability and VOC carbon was observed. The 2-nonanone (50–250 ppm) released from O/W emulsions increased the foliar length on L. 〈em〉sativa〈/em〉 and 〈em〉S. lycopersicum〈/em〉. Additionally, root lateral number was increased in 〈em〉S. lycopersicum〈/em〉 after exposition to released 2-nonanone. Surface elements as carbon, oxygen, and nitrogen were increased on leaves. It empathized that total nitrogen of both vegetables increased with exposition to 2-nonanone. Therefore, O/W emulsions can be an effective tool to microencapsulate VOCs with potential horticulture application.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307265-ga1.jpg" width="442" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Qidong Huang, Xin Li, Sili Ren, Wuhui Luo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Xanthate is a widely used collector in the flotation of sulfide minerals and discharge of xanthate-bearing solution could cause detrimental effects on ecological balance. In this study, the cationic gemini surfactant, butane-1,4-bis(dodecyl dimethyl ammonium bromide) (gBDDA), was applied to modify montmorillonite (Mt) for removal of ethyl, isobutyl, and isoamyl xanthates from aqueous solution. Different amounts of gBDDA that were stoichiometrically equivalent to 0.5 and 1.0 times the cation exchange capacity of Mt were used to investigate the effects of gBDDA dosage on xanthates removal by the obtained products (gOMt). Characterization results of gOMt by X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis showed the successful intercalation of gBDDA into the interlayer space and the higher content of gBDDA on the external surface of gOMt-1.0. Ion exchange and hydrophobic interaction accounted for the similar adsorption capacities of gOMt-1.0 for three xanthates (ca., 0.6 mmol/g), regardless of the molecular structure of xanthates. The rapid adsorption rate and high selectivity of gOMt to xanthates were obtained as supported by the complete removal within 60 min and the stable uptake in the sulfate-coexisting system, respectively, suggesting that gOMt could be a promising adsorbent for removal of xanthates from aqueous solution.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307125-ga1.jpg" width="424" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 6 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Yi Xiao, Zeqing He, Renshan Wang, Xueqin Tao, Benxia Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Notwithstanding intensive research in recent decade, the conspicuous restrictions in photocatalysts still remain as low utilization of visible light, poor charge transfer/separation, and insufficient surface active sites. Designing semiconductor heterostructures as photocatalysts is a promising approach to enhance the photocatalytic efficiency for degrading organic pollutants. In this work, a novel WO〈sub〉3〈/sub〉/BiOCl p–n heterostructure photocatalyst with optimal molar ratio was successfully fabricated by growing BiOCl nanosheets on WO〈sub〉3〈/sub〉 nanofibers through the electrospinning method followed with a solvothermal process. The optical properties and photoelectrochemical tests indicated that the WO〈sub〉3〈/sub〉/BiOCl heterostructures possess high ability of photogenerated charge separation. The photocatalytic performance of the as-obtained materials was assessed by the degradations of rhodamine B (RhB) and phenol in water under visible light. Compared with pure WO〈sub〉3〈/sub〉 nanofibers and BiOCl nanosheets, the WO〈sub〉3〈/sub〉/BiOCl heterostructure catalysts showed improved photocatalytic efficiencies, and the apparent rate constant of RhB degradation is 0.259 min〈sup〉−1〈/sup〉 on the optimal WO〈sub〉3〈/sub〉/BiOCl(2) sample, which is about 2.3 times that of pure BiOCl (0.113 min〈sup〉-1〈/sup〉). The roles of different active species in the photocatalytic system were determined by active-species-eliminating experiments, revealing that the photogenerated holes play a leading function in the degradation of organic pollutants. The enhanced photocatalysis of WO〈sub〉3〈/sub〉/BiOCl(2) heterostructures results from the joint effect of high activity of BiOCl nanosheets, anti-agglomeration of WO〈sub〉3〈/sub〉 nanofibers, and well-matched straddling band-structures for charge separation. This photocatalyst presents great potential in the removal of organic pollutants from aquatic environment.〈/p〉〈/div〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571930740X-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈p〉The novel WO〈sub〉3〈/sub〉/BiOCl heterostructure photocatalyst exhibits improved photocatalysis for degrading organic pollutants under visible light.〈/p〉 〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): O. Gmach, A. Bertsch, C. Bilke-Krause, U. Kulozik〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The aim of this study was to investigate the effect of oil type, i.e. sunflower, rapeseed, peanut and corn oil on the emulsification effect. Knowledge about the impact of the different oils on the emulsification process in a head-to-head comparison is lacking. The hypothesis was that various oils as such or with their special compositions of by-products will have an impact on the properties of the resulting emulsion. As a novel aspect, a single fraction of egg yolk (EY), i.e. the egg yolk granules, were used as emulsifier. Because of their different sources and production processes, the oils differ in composition of fatty acids, degree of saturation and contain various surface-active components like cell membrane fragments, phospholipids and vitamins which influence the emulsification process and therefore the emulsions. In addition, the pH value of the aqueous phase was varied in a broad range. The dynamic interfacial tension between oil and water as well as the adsorption behavior of granules at the interface was analyzed by drop shape analysis. Oil-in-water emulsions with high ratio of dispersed phase (80%) were produced using a colloid mill. The resulting particle size distribution was determined by laser diffraction. There were significant differences in interfacial tension and adsorption of surface-active components at the interface among the oils due to their composition, fatty acid chain length and ratio of mono-, di-, and triglycerides, resulting in different droplet sizes ascribable to the oils. A correlation could be found for the initial decrease of the analytically measured interfacial tension at the oil-water interface and the resulting emulsion droplet size. Furthermore, it could be shown that the droplet size of the emulsions decreased with increasing pH-value of the continuous phase.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307769-ga1.jpg" width="482" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): Yulia V. Kuznetsova, Ilse Letofsky-Papst, Benedikt Sochor, Bernhard Schummer, Alexander A. Sergeev, Ferdinand Hofer, Andrey A. Rempel〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A simple shell-creating technique for the synthesis of CdS nanoparticles covered by ZnS is presented, which also contributes to the understanding of their low quantum yield and luminescence intensity in water, which is usually below 0.01%. The CdS nanoparticles with about 0.8 nm thick ZnS shell were synthesized in a colloidal aqueous solution and stabilized by EDTA. The CdS carrier lifetime and the quantum efficiency is greatly increased. For the latter, values up to 2.7% were achieved. A mechanism for the CdS nanoparticle luminescence in the aqueous solution is proposed, which is based on radiative recombination of charge carriers with structural defects. It was found that the synthesis of CdS in air leads to the inclusion of oxygen atoms in the structure of nanoparticles, which strongly effects the luminescence spectrum. These results show that most of the CdS luminescence centers are localized inside the nanoparticle.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719308027-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 12 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Ali Esfandyari Bayat, Reza Shams〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In recent decades, utilizing of water-based muds (WBMs) in drilling oil and gas wells is ever increasing comparing to oil-based muds and synthetic-based muds due to the lower environmental issues. However, the main drawbacks with WBMs are rheological properties inefficiency and shale swelling which have caused attentions turn to improvement of WBMs’ rheological properties. In this study, the effects of various nanoparticles (NPs) namely titanium dioxide (TiO〈sub〉2〈/sub〉), silicon dioxide (SiO〈sub〉2〈/sub〉), and zinc oxide (ZnO) on improving rheological properties and shale recovery rate of a WBM sample at two temperatures (25 and 50 °C) were investigated. The concentrations of NPs in the base mud were set at 0.01, 0.05, 0.1 and 0.5 wt%. The results revealed that by adding NPs, the plastic viscosity (PV) of base mud was noticeably increased at the both temperatures. The optimum concentration of all NPs for increasing PV was found to be 0.01 wt%. Furthermore, by increasing concentration of ZnO and SiO〈sub〉2〈/sub〉 NPs up to 0.5 wt%, the base mud yield point value was considerably risen to around 13.3%, while by increasing concentration of TiO〈sub〉2〈/sub〉 NPs, the mud yield point values were reduced to 23.5 and 20.2 (lb/100 ft〈sup〉2〈/sup〉) at 25 and 50 °C, respectively. The optimum ZnO, TiO〈sub〉2〈/sub〉, and SiO〈sub〉2〈/sub〉 NPs concentrations for this purpose were found to be 0.05, 0.01, and 0.1 wt%, respectively. Moreover, ZnO and SiO〈sub〉2〈/sub〉 NPs at concentrations below 0.05 wt% had the best performances for filtration loss control. The related reason is higher stability of these NPs in the aqueous phase and consequently, better mud cake pores filling act by them which caused the mud cakes permeabilities were noticeably reduced. Besides that, SiO〈sub〉2〈/sub〉 NPs caused the highest 10 sec and 10 min gel strength values and ZnO and TiO〈sub〉2〈/sub〉 NPs in order had the lowest 10 sec and 10 min gel strength values at all applied concentrations and temperatures. Finally, by increasing concentrations of all NPs, shale recovery rates have noticeably risen comparing to the base mud. SiO〈sub〉2〈/sub〉, ZnO and TiO〈sub〉2〈/sub〉 NPs in order were successful additives for shale recycling.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307800-ga1.jpg" width="292" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 13 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Ming Yang, Qianhui Bai〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Water pollution has become a great problem and aroused worldwide concern. As a new class of materials, metal-organic frameworks (MOFs) exhibit significant potential for wastewater treatment due to their high surface area, porosity, stability and tunability. In this work, flower-like hierarchical Ni-Zn MOF microspheres were synthesized via a facile solvothermal method. The mole ratio of Ni to Zn had a great influence on the morphology and microstructure of the final products. With the increase mole ratio of Zn to Ni, the morphology of MOFs gradually changed from spheroidal structure to rod-like structure. Using the Congo red (CR) experiment to evaluate the adsorption performance, Ni-Zn MOF displayed superior adsorption capacity towards CR (460.90 mg g〈sup〉-1〈/sup〉), compared with Ni MOF (276.70 mg g〈sup〉-1〈/sup〉) and Zn MOF (132.20 mg g〈sup〉-1〈/sup〉). Besides the tuned morphology and pore structure, electron transferring from Zn species to Ni species would also favor the physicochemical adsorption of Ni-Zn MOF towards CR.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307836-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈p〉Ni-Zn MOF synthesized via solvothermal method exhibited a superior adsorption performance towards Congo red. Due to the synergistic effect of Ni and Zn species, the Ni-Zn MOF exhibited a superior adsorption performance compared with Ni MOF and Zn MOF.〈/p〉 〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): Yanyan Pei, Zhuwu Jiang, Liangjie Yuan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Recently, MgO has been demonstrated to be a promising adsorption material for dye removal from wastewater due to its unique characteristics. However, the low surface area and recyclability have seriously limited its practical application in water treatment. Herein, MgO was introduced to mesoporous MCM-41 to improve its surface properties. A series of MCM-41/MgO nanocomposites with high surface areas (˜1000 m〈sup〉2〈/sup〉/g) and mesostructures were synthesized by a facile in situ method. Compared with pure MgO and MCM-41, the mesoporous MCM-41/MgO exhibited enhanced adsorption capacity and superior recycling stability for fast removal of an organic dye from water. The maximum adsorption capacity for crystal violet (CV) can reach 1861.38 mg/g, which is several times higher than that of MgO itself and of most other adsorbents. Even after five consecutive cycles, the removal efficiency is still up to 90%. It is expected that the mesoporous MCM-41/MgO materials will have a considerable potential in wastewater treatment.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉A facile synthetic strategy was developed to fabricate MCM-41/MgO nanocomposities with ultrahigh adsorption performance and excellent recycling stability.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719308040-ga1.jpg" width="403" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 20 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 581〈/p〉 〈p〉Author(s): Shasha Ai, Xu Guo, Lei Zhao, Dan Yang, Hanming Ding〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Prussian blue analogues (PBAs) have gained extensive attention for peroxymonosulfate (PMS) activation. However, the poor recovery ability of PBAs has limited their practical applications. In this work, PBA was firstly immobilized using zeolitic imidazolate framework-8 (ZIF-8) 〈em〉via〈/em〉 a facile 〈em〉in-situ〈/em〉 growth method. The decoration of PBA onto the surface of ZIF-8 was well confirmed by TEM, XRD, FTIR and XPS. The catalytic efficiency of the PBA-ZIF8 composite was significantly higher than that of pure PBA and ZIF-8 on the activation process of peroxymonosulfate when rhodamine B (RhB) was employed as a target contaminant. RhB degradation efficiency was effectively promoted at relatively high PBA-ZIF8 dosage and PMS concentration, as well as in near-neutral pH medium. Sulphate radicals obviously played a predominant role in attacking RhB during the whole reaction. In addition, PBA-ZIF8 also possessed good stability and reusability with negligible cobalt leaching. Therefore, the PBA-ZIF8 composite was a conveniently prepared and promising catalyst that may be employed to remediate contaminated water due to its excellent catalytic activity and recyclability.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307848-ga1.jpg" width="408" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 15 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Qingsong Hu, Sheng Yin, Yi Ding, Ting Wu, Ming Li, Bin Wang, Yong Chen, Jun Di, Jiexiang Xia, Huaming Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel sphere-like g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉/PbBiO〈sub〉2〈/sub〉Cl 2D-3D composite photocatalyst was fabricated 〈em〉via〈/em〉 a reactive ionic liquid 1-hexadecyl-3-methylimidazolium chlorine ([C〈sub〉16〈/sub〉mim]Cl) assisted one-pot solvothermal method. [C〈sub〉16〈/sub〉mim]Cl could act as Cl source, dispersing and template agent in the meantime, which ensured the construction of PbBiO〈sub〉2〈/sub〉Cl porous microspheres and high dispersity of ultrathin g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉. Various techniques were adopted to investigate the morphology, structure, optical and electrochemical properties of the obtained catalysts. It could be observed that ultrathin g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 was dispersed evenly around PbBiO〈sub〉2〈/sub〉Cl microspheres. The colorless contaminants including bisphenol A (BPA), ciprofloxacin (CIP) and colored rhodamine B (RhB) were selected as the model pollutants to appraise the photocatalytic performance of the as-prepared samples. Compared with single PbBiO〈sub〉2〈/sub〉Cl, the composites presented obviously enhanced photocatalytic performance under the irradiation of visible light, and the optimum mass ratio of g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 was around 3 wt%. The improvement of photocatalytic activity could be ascribed to the tight interfacial contact between the two components that could promote the separation and transfer of photogenerated electron-hole pairs. Superoxide radical (•O〈sub〉2〈/sub〉-), holes and hydroxyl radical (•OH) all participated in the photocatalytic reactions on account of radicals quenching experiments and electron spin resonance (ESR). This research extends the knowledge into the construction of other 2D-3D composite photocatalysts with preferable photocatalytic activities in the field of environmental remediation.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307927-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Jiajia Lu, Yanxia Kou, Xiangmei Jiang, Meijuan Wang, Yuanyuan Xue, Bowen Tian, Liang Tan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As the sensing film on the electrode surface, some composites consisted of the conducting polymer and the different types of nanomaterials exhibit the improved electroconductivity and catalytic ability in comparison with those composed of the individual components. But their preparation generally requires a multi-step and relatively complicated process. Here a glassy carbon electrode (GCE) modified with poly(glyoxal-bis(2-hydroxyanil)) (PGBHA), amino-functionalized graphene quantum dots (afGQDs) and MnO〈sub〉2〈/sub〉 nanoclusters (MnO〈sub〉2〈/sub〉 NCs) was fabricated based on a one-pot protocol using the cyclic voltammetric scan. The scanning electron microscopy, infrared spectroscopy and X-ray photoelectron spectroscopy measurements confirmed the existence of the PGBHA-afGQDs film doped by MnO〈sub〉2〈/sub〉 NCs on the GCE surface. The charge transfer on this chemically modified electrode could be well achieved, which was revealed by the cyclic voltammetry and electrochemical impedance spectroscopy. The prepared electrochemical sensor was employed for the simultaneous determination of vitamin B2 (V〈sub〉B2〈/sub〉) and dopamine (DA) by using differential pulse voltammetry. The linear detection range of V〈sub〉B2〈/sub〉 and DA was obtained from 0.1 to 100 μM under the optimized conditions and the detection limits were measured to be 0.04 μM and 0.05 μM, respectively.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719306284-ga1.jpg" width="212" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Yaxiong Ji, Hong Zhong, Ping Chen, Xu Xu, Yuanhao Wang, Hai Wang, Guangyan Liu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The superiority of asymmetric gemini surfactant over the symmetric one is unveiled in case of organo-vermiculite (organo-Vt) for the first time. A common asymmetric gemini surfactant [C〈sub〉22〈/sub〉H〈sub〉45〈/sub〉(CH〈sub〉3〈/sub〉)〈sub〉2〈/sub〉N〈sup〉+〈/sup〉(CH〈sub〉2〈/sub〉)〈sub〉2〈/sub〉N〈sup〉+〈/sup〉(CH〈sub〉3〈/sub〉)〈sub〉2〈/sub〉C〈sub〉10〈/sub〉H〈sub〉21〈/sub〉]Br〈sub〉2〈/sub〉 (marked as 22-2-10) was adopted as modifier onto the vermiculite (Vt) to prepare adsorbent targeted at methyl orange (MO) and 〈em〉p〈/em〉-chlorophenol (PCP) in single and/or binary systems. The superiority of surfactant asymmetry on the structure of organo-Vt adsorbents was disclosed by larger interlayer spacing, more modifier loading, higher surfactant availability as well as the stronger adsorption capacity of organo-Vt modified by 22-2-10 (22-2-10-Vt) compared with organo-Vt modified by the corresponding symmetric modifier [C〈sub〉16〈/sub〉H〈sub〉33〈/sub〉(CH〈sub〉3〈/sub〉)〈sub〉2〈/sub〉N〈sup〉+〈/sup〉(CH〈sub〉2〈/sub〉)〈sub〉2〈/sub〉N〈sup〉+〈/sup〉(CH〈sub〉3〈/sub〉)〈sub〉2〈/sub〉C〈sub〉16〈/sub〉H〈sub〉33〈/sub〉]Br〈sub〉2〈/sub〉 (16-2-16-Vt). Effective retention of MO (142 mg g〈sup〉−1〈/sup〉) and PCP (85 mg g〈sup〉−1〈/sup〉) in single system were fitted by the pseudo-second-order, Langmuir and intra-particle diffusion models. Particularly, organic-matter-corrected sorption coefficient (〈em〉K〈sub〉OM〈/sub〉〈/em〉) was introduced to verify the partition process, which was found dominant in the adsorption processes and further promoted by hydrogen bond, intermolecular interaction and π-π interactions. The practical feasibility of 22-2-10-Vt was achieved in binary system, where the total adsorbate retention (0.74 mmol g〈sup〉-1〈/sup〉) was higher than that in single systems (0.54 or 0.31 mmol g〈sup〉-1〈/sup〉 for MO and PCP, respectively). An orderly gradient adsorption process was proposed in the binary system due to the stronger hydrophobicity of MO than PCP. The adsorbed adsorbents were regenerated by ethanol at least for three cycles in binary systems. The results obtained could not only throw lights on asymmetric modifiers and the related analogues, but also extend to the feasibility of organo-Vts in the multi-component water environment.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307289-ga1.jpg" width="348" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Peng Sun, Linfeng Li, Shanyi Guang, Hongyao Xu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In order to study the effect of dipole-dipole action direction and molecular space configuration on supramolecular self-assembly of azobenzene, three azobenzene dye molecules N1 (" linear "), N2 (" L ") and N3 (" U ") were designed. First, the feasibility of molecular design is verified by theoretical calculations and then synthesized by experiments. By adjusting the direction of the molecular dipole moment and the spatial configuration of the molecule, the three dye molecules self-assemble to form supramolecular self-assemblers with different structures. The properties of three azobenzene dye molecules were studied by IR、NMR、 X-ray diffraction and UV–vis spectra. Theoretical calculation and experimental results show that the direction of dipole dipole interaction and molecular space configuration have important effects on the supramolecular self-assembly morphology of azobenzene.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307307-ga1.jpg" width="213" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Elhamolsadat Ghorbi, Mehrnoush Namavar, Vahideh Rashedi, Saeideh Farhadinejad, Siamak Pilban Jahromi, Mohsen Zareian〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The study investigated influence of copper oxide nanoparticle (CuO NP) concentrations on the bactericidal properties of silver-copper oxide (Ag/CuO) nanocomposite against 〈em〉Escherichia coli〈/em〉 PTCC 1329, 〈em〉Klebsiella pneumoniae〈/em〉 PTCC 1290 and 〈em〉Staphylococcus aureus〈/em〉 PTCC 1189. Silver–copper oxide nanocomposite with varying concentrations of CuO was synthesized using a facile sol–gel combustion route. Formation of Ag/CuO crystalline structure and particle size were characterized by X-ray diffraction, Transmission Electron Microscopy and Field Emission Scanning Electron Microscopy. Elemental analyses were performed by energy dispersive X-ray. Morphologies of CuO NPs showed that Ag/CuO nanocomposite consisted of interconnected nanoparticles with a porous channel. Ag/CuO nanocomposite with higher CuO NPs content exhibited superior bactericidal effects. Bacterial growth profile also confirmed superior bactericidal effects of the nanocomposite at higher CuO NPs concentrations. A facile sol–gel technique with enhanced bactericidal effects at higher concentration of CuO NPs is promising for the development of cost-effective and efficacy-enhanced nanomaterials.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307204-ga1.jpg" width="363" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Keigo Tashiro, Suzuko Yamazaki〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We fabricated 5,10,15,20-tetra(4-pyridyl)porphyrinatozinc(II) (ZnTPyP) fibers by utilizing surfactant-assisted method with cetyltrimethylammonium bromide (CTAB). The ZnTPyP fibers became longer as molar ratio of CTAB to ZnTPyP (γ) increased. In the case of γ ≥ 50, the Soret band of ZnTPyP monomer was observed after stirring for 1 h and was split into two peaks after the aging at 40 °C for more than 5 days. On the other hand, such split peaks were observed without the aging when the γ value was 10 or 20. These findings suggest that CTAB interacts with the ZnTPyP monomer in aqueous solution to form micelles, and the fibers are gradually constructed by self-assembling the stabilized ZnTPyP monomer. Photocatalytic activity of the ZnTPyP fibers was evaluated for the degradation of rhodamine B (RhB) in water under visible light (VL) irradiation. The highest photocatalytic activity was obtained at γ = 150–300, indicating that the fibers with 1.3–2.0 μm were the most suitable as photocatalyst. When air was bubbled in the reaction solution, the photocatalytic activity was higher than that under N〈sub〉2〈/sub〉 bubbling. However, absorption peak attributed to the ZnTPyP fibers decreased under air bubbling although it remained almost constant under N〈sub〉2〈/sub〉 bubbling. These results suggest that the ZnTPyP fibers can act as photocatalyst and active oxygen species such as O〈sub〉2〈/sub〉〈sup〉•−〈/sup〉 radical might decompose the ZnTPyP fibers. Kinetic studies were performed to clarify the degradation mechanism of RhB under the experimental condition where the decomposition of the ZnTPyP fibers was negligible.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307290-ga1.jpg" width="368" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 580〈/p〉 〈p〉Author(s): Helena M. Heidemann, Marta E.R. Dotto, João B. Laurindo, Bruno A.M. Carciofi, Cristiane Costa〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Since starch hydrophilicity makes it difficult to be used as packaging material, its combination with synthetic biodegradable polymers is an alternative of interest. In this work, atmospheric air cold plasma was used as an adhesion improver between polycaprolactone (PCL) or poly(lactic acid) (PLA) and starch layers, in order to produce multilayer films. For this, a barrier dielectric discharge plasma reactor was used, at ambient temperature and atmospheric pressure. The treatment of PCL and PLA films resulted in increase of the surface roughness and decrease of the water contact angle. Multilayer films (PCL-, PLA-starch) were produced after plasma treatment. Adhesion of starch films onto both PCL and PLA surfaces was improved with plasma treatment, and the delamination resistance increased with treatment time. The best adhesion was obtained for PLA-starch film with 10 min of plasma treatment, resulting in no delamination. The water vapor barrier of the multilayer films was significantly higher than of starch films, while the mechanical properties were similar to those found for PCL/PLA films, showing that these multilayer films are promising for package applications.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719307277-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 562〈/p〉 〈p〉Author(s): Parisa Moazzam, Giorgio Luciano, Amir Razmjou, Ehsan Akbari, Pavel G. Ul’yanov, Soumitro Mahanty〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The degree of available energy on a surface determines how a surface interacts with its surrounding environment such as corrosion. Current approaches to protection of Aluminum surfaces from corrosion mainly focus on adding an organic or inorganic layer to either act as a barrier from oxidant or scarifying to inhibit the corrosion. Altering the surface energy of Al on a molecular level is another alternative approach to efficiently modify the Al surface without the need for another thick expensive protective or scarifying materials. Herein, an attempt was made to understand how a molecular scale energy alteration improves the anticorrosion behavior of an aluminum surface. Two different surface engineering alteration strategies have been discussed; termed ALOSH and ALTSH modification. A variety of analytical instruments, i.e., FTIR, EDAX, XPS, SEM, AFM, WCA, and SFE measurement were used to systematically characterize the samples. Electrochemical impedance spectroscopy revealed that there are different resistances after the surface modifications. The trapping air resistance appeared in ALTSH is approximately 2.4 and 36 times higher than that of ALOSH and bare samples, respectively. The potentiostat analysis results showed that the mili inch per year value of coating for ALTSH was 0.012 while that of ALOSH was 0.507. It was also found that the low surface energy alteration without using inert molecules is not enough to render corrosion inhibition property, as it needs to have a protective energy barrier with no or minimal active electrochemical behavior.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718311294-ga1.jpg" width="320" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 561〈/p〉 〈p〉Author(s): Corina L. Reichert, Hanna Salminen, Gabriela Badolato Bönisch, Christian Schäfer, Jochen Weiss〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The concentration ratio of binary surfactant systems can alter the interfacial layer properties, and consequently affect emulsion stability. To study the effect of varying concentration ratios (〈em〉r,〈/em〉 % w/w) of interfaces containing 〈em〉Quillaja〈/em〉 saponins and other naturally occurring food-grade surfactants on their emulsifying properties, we evaluated particle size, ζ-potential, and appearance of 10% oil-in-water emulsions (pH 7) stabilized by 〈em〉Quillaja〈/em〉 saponin - protein or 〈em〉Quillaja〈/em〉 saponin - lecithin mixtures. 〈em〉Quillaja〈/em〉 saponin - Na-caseinate mixtures (〈em〉r〈/em〉 = 0.3:0.2, 0.2:0.3, and 0.1:0.4) formed small emulsion droplets (d〈sub〉43〈/sub〉: 0.2 – 0.3 μm), whereas at 〈em〉r〈/em〉 = 0.4:0.1, the emulsions contained micron-sized droplets (d〈sub〉43〈/sub〉: 1.217 ± 0.558 μm). Emulsions formed by 〈em〉Quillaja〈/em〉 saponin - pea protein mixtures flocculated at 〈em〉r〈/em〉 = 0.3:2.0, 0.2:3.0, and 0.1:4.0. In contrast, 〈em〉Quillaja〈/em〉 saponin - rapeseed lecithin or egg lecithin mixtures were able to generate small emulsion droplets (d〈sub〉43〈/sub〉: 0.2 – 0.5 μm) at all tested concentration ratios. The formation of stable emulsions using binary mixtures of naturally occurring emulsifiers was more dependent on the concentration ratio of the proteins than lecithins, indicating that the interfacial behavior of 〈em〉Quillaja〈/em〉 saponins is more sensitive to the presence of proteins. This was attributed to attractive molecular interactions yielding complexes at interfaces and/or in the continuous phase. This study shows that food-grade binary surfactant mixtures can be used to form stable emulsions with properties being tunable by altering the mixing ratios between surfactants.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571831522X-ga1.jpg" width="429" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 561〈/p〉 〈p〉Author(s): Li Wang, Jingyi Wang, Chi He, Wei Lyu, Wenlong Zhang, Wei Yan, Liu Yang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To improve the biochar’s adsorption performance towards phosphate as well as to endow the biochar with magnetic property, novel rare earth element doped magnetic biochars, Ce/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC and La/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC, were prepared by separately co-precipitating cerium (Ce) and lanthanum (La) with FeCl〈sub〉3〈/sub〉, FeCl〈sub〉2〈/sub〉 and biochar. For comparison, Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC without doping Ce or La was also synthesized. The characterization results indicated that Ce and La ions were successfully doped into the magnetite. The La/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC had higher magnetic saturation and point of zero charge than Ce/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC. A series of batch experiment results demonstrated that the phosphate adsorption capacity of biochar has been greatly improved after Ce or La doping, especially La. The phosphate adsorption capacity of La/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC was 20.5 mg/g at pH 6.5, which was 1.6 and 2.9 times than that of Ce/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC and Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC, respectively. The adsorption kinetics and isotherms of phosphate onto La/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC and Ce/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC were best fitted by the pseudo-second order and Freundich model, respectively, indicating that the adsorption process was a multilayer process and controlled by chemical reaction. The combined results of batch experiments and physiochemical analyses revealed that the possible mechanisms were the formation of inner-sphere complex at neutral conditions and electrostatic attraction between positively charged adsorption sites and phosphate under acid conditions. The enhanced phosphate adsorption performance and endowed magnetic property indicated La/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉-BC could be used as a promising adsorbent in phosphate removal.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718312615-ga1.jpg" width="455" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Rahul Saha, Ramgopal V.S Uppaluri, Pankaj Tiwari〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Experimental investigations targeting optimum chemical slug formulations for tertiary enhance oil recovery of heavy crude oil in carbonate reservoir were carried out. Based on interfacial tension (IFT), emulsification, wettability alteration and core flooding studies, two alkalis and eight surfactants have been screened by considering conditions similar to oil reservoirs (0–20% salinity and 30–80 °C temperature). Dynamic IFT studies interestingly affirmed oil-layer break time phenomena and hence enhanced emulsification extent. Alkali, thermally stable surfactant mixture and alkali-surfactant mixture systems reduced IFT to 10〈sup〉−1〈/sup〉, 10〈sup〉−2〈/sup〉 and 10〈sup〉−3〈/sup〉 mN/m respectively. Flooding studied confirmed an additional oil recovery of 12.79% and 14.46% for alkali and alkali-surfactant mixture systems respectively. On the other hand, due to optimal emulsion stability, maximal residual oil recovery of 24.58% being achieved for a slug formulation of 0.1 wt% surfactant mixture. Surfactant concentration above 0.1 wt% enabled stronger emulsion formation that detriments displacement efficiency and oil recovery factor.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718311178-ga1.jpg" width="341" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Mi Zhang, Jilai Gong, Guangming Zeng, Peng Zhang, Biao Song, Weicheng Cao, Hongyu Liu, Shuangyan Huan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As a photocatalyst, bismuth vanadate coupled with reduced oxide graphene (BiVO〈sub〉4〈/sub〉-rGO) has been reported for dye degradation. However, this catalyst faced the disadvantages of low catalytic efficiency and long catalytic time. In this paper, BiVO〈sub〉4〈/sub〉-rGO composites were synthesized by a modified hydrothermal method, and characterization results showed the monoclinic BiVO〈sub〉4〈/sub〉 surface successfully coupled with a layer of rGO. The dye removal performance of BiVO〈sub〉4〈/sub〉-rGO composites were evaluated by the degradation of malachite green and rhodamine B under visible light irradiation and photocatalytic results showed that the BiVO〈sub〉4〈/sub〉 with rGO modification could effectively enhance the dyes removal performance. In a specific photocatalytic experiment, BiVO〈sub〉4〈/sub〉-rGO-300 could remove 99.5% MG in two hours and 99.84% RhB in four hours, which was superior to previous studies. Furthermore, application of catalyst in practical wastewater was also taken into account. MG and RhB were degraded by BiVO〈sub〉4〈/sub〉-rGO in several kinds of actual wastewater and experimental results showed that this catalyst could efficiently remove dye in actual environment. This improvement could be ascribed to the increase of special surface area, efficient charge transfer and reduction of electron-hole pair recombination with the incorporation of rGO. The influences of pH, supporting electrolyte and mechanism of the dye degradation were also investigated in details.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉The dyes removal performance for MG and RhB was effectively enhanced and the catalyst has a good potential in dye wastewater treatment.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571831135X-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Min Jae Shin, Young Jae Shin, Jae Sup Shin〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, the molecular imprinting technique and self-assembled monolayer technique were combined to increase the recognition ability of cholesterol. A self-assembled monolayer with 4-mercaptophenol and benzenethiol was formed on a gold plate, and the reaction of cholesteryl chloroformate with the phenol group in the 4-mercaptophenol was followed. This layer was then coated with poly(methyl methacrylate) (PMMA). In order to expose the cholesterol buried under the coating, the partial upper part of the coated PMMA was then removed by stroking the coated plate in acetone solvent. The molecular imprinted site was prepared by hydrolysis of the carbonate bond and extraction of the hydrolyzed cholesterol. This gold plate was used as a working electrode to test the recognition ability for cholesterol. The result showed that the plate obtained good recognition ability for cholesterol compared with cholic acid. The ratio of 4-mercaptophenol to benzenethiol was a very important factor in the ability to recognize cholesterol. Regulating the thickness of the coated PMMA was also one of the important factors to increase the ability to recognize cholesterol.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571831238X-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Nichaphat Thongsai, Nattapong Tanawannapong, Janjira Praneerad, Sumana Kladsomboon, Panichakorn Jaiyong, Peerasak Paoprasert〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rice husk, an agricultural waste that currently finds few uses, is rich in cellulose-based materials and silica. In this work, a simple one-pot method for preparing carbon dots and mesoporous silica from rice husk was developed, using hydrothermal and calcination methods. The carbon dots exhibited blue emission with excellent photostability, and had a diameter of 4–5 nm and a quantum yield of 3%. They were demonstrated to be capable of detecting alcohol vapors at room temperature, and of distinguishing between methanol, ethanol, and several volatile organic compounds when used as the sensing layer in an optical electronic nose system. The alcohol content of a commercial beverage was successfully determined using the carbon dot-integrated electronic nose. The solvation effect of the alcohol vapors on the electronic absorption spectra of model carbon dot structures was illustrated using time-dependent density functional theory with the dielectric polarizable continuum model. The UV–vis and computational results confirmed that the sensing mechanism of carbon dots is through the modulation of their optical absorbance governed by polar-polar interfacial interactions. This was experimental and computational demonstration of carbon dot sensing of vapors. Their excellent biocompatibility suggests biomedical applications, in addition to sensing. The production of two functional materials from a single low-value waste source was demonstrated.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718312378-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Chenhao Zhao, Zhibiao Hu, Jiangshui Luo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Porous carbon box or nanoplate has been prepared by synchronous carbonization/activation of potassium citrate, and the corresponding porous carbon nanoplate/Se composite can be obtained using a melting-diffusion method. The influence of structure parameters including specific surface area and porous structure of porous carbon and resultant carbon/Se composite on electrochemical properties are studied. It is found a moderate micropore size of carbon substrate and low specific surface area of carbon/Se composite are benefit to electrochemical performances. At an optimal temperature of 700 °C, the porous carbon composed of micro- and small meso-porous (2–4 nm) structure has a BET specific surface area of 695.4 m〈sup〉2〈/sup〉 g〈sup〉−1〈/sup〉, and the amorphous Se is uniformly encapsulated into its porous structure. As the cathode material of Li ion battery, the porous carbon nanoplate/Se composite delivers an initial discharge capacity of 589.2 mAh g〈sup〉−1〈/sup〉 with Coulombic efficiency of 72.6% at 0.2C, and capacity retention of 78.3% can be obtained after 500 cycles at 2C. Even at a high rate of 4C, a discharge capacity of 415.2 mAh g〈sup〉−1〈/sup〉 can be reached.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718312950-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Ting Zou, You Han, Xinxue Li, Wei Li, Jinli Zhang, Yan Fu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Controlled synthesis of noble metal nanocatalysts with desirable catalytic activities remains a great challenge. Inspired by electron-rich functional groups and supramolecular assembly properties of natural nucleotides, herein we propose a versatile approach to construct Pd nanocatalysts through employing seven nucleotides as both electron donors and stabilizers. The catalytic performance of nucleotide-Pd complexes are greatly associated with the chemical structures of nucleobases as well as the number of phosphate groups. Guanosine 5′-triphosphate-Pd complexes possess high activities in the hydrogenation reduction of 4-nitrophenol assisted by NaBH〈sub〉4〈/sub〉, with the relative rate constant of 7770 min〈sup〉−1〈/sup〉 mM〈sup〉−1〈/sup〉 at 25 °C. Pd(II)-coordinated nucleotides are also promising in NaBH〈sub〉4〈/sub〉-mediated degradation of organic dyes. This work demonstrates a green and facile process to construct Pd nanocatalysts containing abundant active sites under the assistance by natural nucleotides.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718314377-ga1.jpg" width="471" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Mirela Teodorescu, Maria Bercea, Simona Morariu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present study has been focused on investigation of some polymer mixtures of interest for biomedical applications. Three pairs of polymers, namely: poly(vinyl alcohol) (PVA)/poly(vinylpyrrolidone) (PVP), PVA/hydroxypropyl cellulose (HPC), Pluronic F127 (PL)/HPC were subjected to viscometic study in dilute solution. The intrinsic viscosity, the Huggins constant and 〈em〉B〈/em〉 parameter, as well as the miscibility parameters were discussed. The hydrodynamic properties of these polymer mixtures were analyzed as compared with the corresponding single polymer solutions at two reference temperatures, 〈em〉i.e.〈/em〉 the storage (25 °C) and physiological (37 °C) temperature. Each mixture has shown distinct behavior: PVA/PVP system is fully miscible regardless composition or temperature; the miscibility of PVA/HPC or PL/HPC mixtures is influenced in a specific manner by the ratio between the two polymers and by the temperature. The main interest is a better understanding of the polymer-polymer interactions and to identify the synergistic behavior in order to design multicomponent biomaterials with targeted properties. The compatibility of these polymers was attributed to the favorable hydrogen-bonding interactions between the hydroxyl groups of PVA and carbonyl groups of PVP, hydroxyl groups of PVA and HPC, and ether groups of PL and hydroxyl groups of HPC. On the other hand, hydrophobic interactions influence the polymer/polymer miscibility.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718311749-ga1.jpg" width="225" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Xiaopeng Xue, Zhonghao Xu, Israel Pedruzzi, Ping Li, Jianguo Yu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Interface phenomena between low molecular weight (LMW) carboxylic acids and muscovite was investigated through molecular dynamic simulation and experiment, where the typical monocarboxylic acids including formic acid (C〈sub〉1〈/sub〉), acetic acid (C〈sub〉2〈/sub〉), propionic acid (C〈sub〉3〈/sub〉) and butyric acid (C〈sub〉4〈/sub〉) were used as models. Density distribution, adsorption energy, root mean square dynamic (RMSD) of carboxylic acids on water-muscovite interface were calculated through molecular dynamic simulation, and the advanced characterization methods, such as ATR-FTIR spectra, AFM images and contact angle were performed to test and verify the relative simulation findings. The molecular simulation showed that carboxylic acids adsorbed on surface of muscovite through hydrogen bond between H atom of 〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉COOH functional group of carboxylic acid and O atom of muscovite, belong to outer sphere adsorption, and ATR-FTIR spectra and AFM images confirmed this finding. Adsorption energy for long carbon chain carboxylic acid (C〈sub〉4〈/sub〉) was higher than that for short carbon chain carboxylic acid (C〈sub〉1〈/sub〉, C〈sub〉2〈/sub〉 and C〈sub〉3〈/sub〉) due to the effect of carboxylic acid diffusion on water-muscovite interface. The hydrophilic functional group 〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉COOH of carboxylic acids preferably adsorbed on muscovite surface, while the hydrophobic functional groups 〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉CH〈sub〉3〈/sub〉 and 〈img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉CH〈sub〉2〈/sub〉 of carboxylic acids were far from the muscovite surface. So, the hydrophobicity on muscovite surface increased due to the adsorption of carboxylic acids, which resulted in the increase of contact angle of water on muscovite surface.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718310823-ga1.jpg" width="242" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Guowen Chen, Yuying Fu, Fuge Niu, Hao Zhang, Xiaomeng Li, Xin Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To evaluate the performance of biopolymer fabricated nanoparticle under commercial processing conditions, the stability of gum Arabic (GA)-zein-cur (curcumin) colloidal system was recorded and analyzed. The results showed that GA-zein-cur system is colloidal stable in the pH range of 5–8, however, encapsulated curcumin degraded rapidly as long as the pH changes. As for processing temperature, more than 70 °C will affect the spatial structure of zein and leading to the leak or exposure of encapsulated curcumin which result in the degradation of curcumin. Na〈sup〉+〈/sup〉 has no significant effect on colloidal and chemical performance of nanoparticles while Fe〈sup〉3+〈/sup〉 could penetrate the zein nanosphere and compromise curcumin. Results of our work imply that the protein-based core-shell delivery system has advantages in solubilizing the hydrophobic compounds and has certain ability to protect the encapsulated material against the unfavorable environment.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718308707-ga1.jpg" width="313" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Haiqin Wu, Liang Yan, Liyang Fu, Lan Jin〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The interaction of alizarin with aminophenylboronic acid (ARS-PBA) was used through a new strategy for electrochemical sensors of glucose. In the present work, ARS-PBA complex and the layered double hydroxide nanosheets (LDH nanosheets) were successfully assembled on indium tin oxide (ITO) electrodes via layer by layer technology method. The resulted electrode was characterized by UV–vis, X-ray diffraction (XRD), atomic force microscope (AFM) and scanning electron microscope (SEM) to achieve the morphological, structural and compositional information. Cyclic voltammetry and differential pulse voltammetry were conducted to investigate electrochemical properties of the modified electrode. Moreover, the modified electrode was used as a non-enzymatic sensor for glucose determination, exhibiting good electrochemical properties, fast response time and long-term stability. At the optimum conditions, the constructed electrode sensor shows a linear range of 0∼1.00 μmol/L and a low detection limit of 4.0 nmol/L (S/N = 3) for glucose. On the basis of affinity between glucose and ARS-PBA complex, the functionalized electrode showed a high selectivity toward glucose over other concomitant biomolecues (dopamine, uric acid and ascorbic acid). Therefore, a simple and effective electrochemical method was developed and offers a complementary tool for the detection of glucose.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718313219-ga1.jpg" width="358" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Priyadharsan A., Shanavas S., Vasanthakumar V., Balamuralikrishnan B., Anbarasan P.M.〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The sunlight driven photocatalytic activity of semiconductor based nanocomposites has attracted extensive attention in recent years for environmental remediation and energy applications. Here, we report an effective strategy to synthesis ternary MoS〈sub〉2〈/sub〉-ZnO-reduced graphene oxide (MZG) nanocomposite as a photocatalyst by a facile hydrothermal method. The prepared nanoparticles were characterized by various analytical tools. The basic photocatalytic mechanism of the composite material was exhibited the photoexcited electrons of ZnO can be readily transported to MoS〈sub〉2〈/sub〉 through rGO backbone, reducing the electron-hole pair recombination. The photocatalytic performance was optimized using methylene blue as a model organic dye under natural sunlight irradiation. The results were compared with pure and binary, MZG ternary nanocomposites exhibit superior photocatalytic activity. In a continuation of environmental remediation studies, MZG ternary nanocomposites revealed high antibacterial activity towards 〈em〉Escherichia coli (E.coli)〈/em〉 and 〈em〉Staphylococcus aureus (S.aureus)〈/em〉, highlighting its potential photocatalytic and antibacterial properties at different industrial and medical applications. This study may afford some inspiration for the rational design and facile synthesis of composite catalysts with a high and tunable catalytic property through a green, efficient pathway.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718310835-ga1.jpg" width="233" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Anusha Chandra, Bhuvanesh E, Sujay Chattopadhyay〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Permselectivity and water uptake behaviors of anion exchange membrane (AEM) were investigated with organic acids. Contribution of the number of carboxyl group (acetic acid: AA, malic acid: MA, citric acid: CA) and hydrocarbon chain lengths (formic acid: FA, AA, propionic acid: PA and n-butyric acid: BA) in water uptake and permselectivity values were separately investigated with five different concentrations 0.025, 0.05, 0.075, 0.1 and 0.125 mol·L〈sup〉−1〈/sup〉 of each acid at two different pH 2.0 and 7.5 conditions. Microstructural changes occurring due to interaction of carboxylate anion and NR〈sub〉4〈/sub〉〈sup〉+〈/sup〉 groups of AEM resulted in permselectivity behavior. Permselectivity trend: CA 〈 MA 〈 AA could be explained by counter-ion condensation resulting out of strong counter-ion interactions with AEM fixed charges. Co-ion mobility values could explain variation in permselectivity at pH 2.0 and 7.5. While, water uptake and ionic size were dominant factors to explain the permselectivity trend: FA 〉 AA 〉 PA 〉 BA. Complex nature of interactions due to properties (size, charge, ionic charge density, mobility, diffusivity, stokes radius etc.) of carboxylate anions were explained using diffusivity ratio (counter/co-ion, 〈em〉D〈sub〉2〈/sub〉/D〈sub〉1〈/sub〉〈/em〉), adsorption equilibrium and fraction of dissociated species.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718313906-ga1.jpg" width="276" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Svetlana Fedorenko, Alexey Stepanov, Rustem Zairov, Ondrej Kaman, Rustem Amirov, Irek Nizameev, Kirill Kholin, Ildus Ismaev, Alexandra Voloshina, Anastasiya Sapunova, Marsil Kadirov, Asiya Mustafina〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present work introduces one-pot synthetic route to join ultra-small iron oxides (6 nm) with Gd(III) complexes in small (∼30 nm) silica nanoparticles with high longitudinal and transverse relaxivity values (r〈sub〉1〈/sub〉 = 34.7 mM〈sup〉−1〈/sup〉 s〈sup〉−1〈/sup〉 and r〈sub〉2〈/sub〉 = 64.7 mM〈sup〉−1〈/sup〉 s〈sup〉−1〈/sup〉 at 0.47 T). The design of the nanoparticles is based on the core-shell morphology, where the Gd(III) complexes were doped into the exterior silica layer. The doping mode is the reason for an efficient interfacial hydration and the small suppressing of r〈sub〉1〈/sub〉 by iron oxides. The measurements on the whole body scanner at 1.5 T confirm the high contrasting abilities of T〈sub〉1〈/sub〉 (Gd) and T〈sub〉2〈/sub〉 (iron oxide) components in the nanoparticles. Poor aggregation behavior of the nanoparticles in water is due to high electrokinetic potential value (−78 mV). Greater aggregation of the nanoparticles in the buffer solutions of bovine serum albumin enhances the disturbing effect of iron oxides on the longitudinal relaxation and facilitates the transverse relaxation. The higher surface activity of the nanoparticles results in their greater cytotoxicity versus the silica coated iron oxides, although the cytotoxicity is low in the concentration range which is within the region of interest for MRI technique.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718311166-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Jiwei Lu, Mingjun Sun, Zhitao Yuan, Shengliang Qi, Zhongyun Tong, Lixia Li, Qingyou Meng〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Serpentine, as a common magnesium silicate mineral found in many ores around the world, is usually dispersed/depressed with the dispersants/depressants by adsorbing on the surface of serpentine. Therefore, in this work, the interaction mechanism of the dispersant of sodium hexametaphosphate (SHMP) was investigated in detail though solution chemistry calculations, Fourier transform infrared spectroscopy (FTIR) analyses, zeta potential measurements, adsorption and ion release tests, and molecular dynamics (MD) simulations. Results indicated that anionic components of H〈sub〉2〈/sub〉PO〈sup〉−〈/sup〉〈sub〉4〈/sub〉 and HPO〈sup〉2−〈/sup〉〈sub〉4〈/sub〉 in SHMP, as the predominant and effective species, adsorbed on the Mg and Si sites of the serpentine surfaces, which occurred on the Si site through the electrostatic interaction and on the Mg site through the chemical adsorption. As a result, the surface charge of serpentine was reversed from positive to negative at all pH region examined. In addition, ion release tests confirmed that SHMP dissolved some Mg ions for forming soluble complexes from the serpentine surface into the solution. Thus, the negative charge of it was further enhanced, which would lead to much stronger repulsion between negatively charge valuable minerals (e.g., pentlandite) and serpentine. Thus, the serpentine would be well dispersed with the valuable minerals.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718312329-ga1.jpg" width="398" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Konstantin Popov, Maxim Oshchepkov, Elena Afanas’eva, Elena Koltinova, Yulia Dikareva, Hannu Rönkkömäki〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Scaling in reverse osmosis facilities, boilers, heat exchangers, evaporation plants, and oilfield applications is a serious problem worldwide. A widely used solution for controlling scale deposition is an application of chemical inhibitors. However, irrespective of the broad and a long-term antiscalant application, the mechanisms of scale inhibition are still the matter of discussions.〈/p〉 〈p〉In order to provide a new insight into the mechanism of the scale inhibition, a novel dynamic light scattering (DLS) special technique is used to study the bulk supersaturated gypsum aqueous solutions during the induction period. It is based on the standard Ag nanoparticles (ARGOVIT) injection into the supersaturated gypsum solution. These nanoparticles act as an internal indifferent light scattering intensity reference, and provide a semiquantitative measurement of a relative gypsum particles content in a blank solution and in the system treated with phosphonates: amino-tris(methylenephosphonic acid), ATMP; 1-hydroxyethane-1,1-bis(phosphonic acid), HEDP; 2-phosphonobutane-1,2,4-tricarboxylic acid, PBTC. It is found that ATMP sufficiently reduces the number of gypsum nuclei, spontaneously formed in the supersaturated solutions. The less effective inhibitors of gypsum scaling HEDP and PBTC also reduce the gypsum nuclei number, but to a less extent. A tentative nonconventional mechanism of scale inhibition in the bulk supersaturated aqueous solutions of gypsum is proposed.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718307192-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Hong-Liu Jiang, Jie-Ci Lin, Wei Hai, Hong-Wei Tan, Yu-Wei Luo, Xiao-Lin Xie, Yao Cao, Fu-An He〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, a novel crosslinked porous β-cyclodextrin-based polymer containing carboxylic acid groups (CT-β-CD) was synthesized successfully and characterized by SEM, FTIR, 〈sup〉13〈/sup〉C solid-state NMR, water-contact-angle measurement, and TGA. The resultant CT-β-CD with triple absorption effects including inclusion complextion, porous network capture, and electrostatic interaction was employed as an adsorbent for removing methylene blue dye from aqueous solution, which exhibited several advantages such as high absorption capacity (q〈sub〉max〈/sub〉 = 672 mg/g), rapid absorption rate, good recyclable ability, and selective adsorption for cationic dyes. The influences of initial MB concentration, absorption time, and pH value on the absorption behavior of CT-β-CD for MB were also investigated. In addition, it was found that the pseudo-second-order kinetic and the Langmuir model for adsorption isotherm could be used to describe the MB absorption behavior of CT-β-CD.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718313050-ga1.jpg" width="437" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Qing Fan, Dali Zhou, Lei Yang, Jiabei Zhou, Shuang Yang, Yongqiang Yang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Glass lubricants have great potential in industrial metal forming processes such as hot extrusion of titanium and titanium alloys. In this work, based on the extrusion process of commercial-purity titanium (TA2) at 800 °C, glass lubricants with low melting points are designed. The thermal properties, high-temperature oxidation resistance and friction properties of uncoated and glass-coated TA2 samples are systemically studied, which reveals the good lubricating and anti-oxidation properties of the samples. The glass lubricant melts into a viscoelastic film at 800 °C to insulate TA2 from oxygen and reduce friction, and automatically peel off during cooling due to the significantly mismatched thermal expansion between the glass coating and TA2 substrate. This work provides a guidance for designing glass-based lubricants used in hot extrusion of metals.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571831152X-ga1.jpg" width="322" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): T. Rijnaarts, J. Moreno, M. Saakes, W.M. de Vos, K. Nijmeijer〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Reverse electrodialysis (RED) is a process to harvest renewable energy from salinity gradients. Under lab conditions with artificial salt solutions, promising results have been achieved in recent years. However, in large scale industrial applications, natural waters are used and that poses challenges such as fouling. Fouling of anion exchange membranes (AEMs) by organic matter (e.g. humic acids) has been identified as a possible cause that lowers RED performance with natural waters. In this work, natural river and seawater at the Afsluitdijk (The Netherlands) are used to study the RED performance of six different AEMs. These AEMs are characterized before and after RED experiments with natural waters. The effect of natural fouling is found to be specific for each AEM and highly dependent on their respective chemistries and associated membrane properties. Firstly, aromatic AEMs with a low swelling degree showed a permselectivity decrease as well as membrane resistance increase. Secondly, aliphatic AEMs with a medium swelling degree experienced only a membrane resistance increase. Finally, only a decrease in permselectivity was observed for aliphatic AEMs with large swelling degrees. Subsequently, the effect of AEM fouling is compared to the observed decrease in RED performance and this shows that AEM fouling can only explain a minor part of the losses in open circuit voltage (OCV). The RED power densities dropped by 15–20% over 12 days, independent of the AEMs selected, while the reduced AEM performance could only explain 2–4% of this reduction in power density. This demonstrates that next to AEM fouling, also other factors, such as spacer fouling, are expected to be the dominant fouling mechanism, reducing the performance to a much larger extent.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718313505-ga1.jpg" width="481" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Yibo Ouyang, Jin Zhao, Ri Qiu, Shugang Hu, Yan Zhang, Peng Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bioinspired superhydrophobic and oil-infused surfaces have been recognized as interesting and promising materials for a wide range of applications correlated with water environment, such as corrosion and biofouling inhibition. Which material is the better choice still waits to reveal. In this study, taking stainless steel as the substrate, superhydrophobic and oil-infused surface based on Cu(OH)〈sub〉2〈/sub〉 matrix with prickly chestnut husk morphology is respectively obtained via successive steps. During the preparation of superhydrophobic surface, firstly, discrete Cu particles are electrodeposited onto stainless steel. After that, oxidation of the as-deposited Cu particles leads to the prickly Cu(OH)〈sub〉2〈/sub〉 following a dissolution-crystallization mechanism. Under a mild condition, dodecanethiol vapor modifies prickly matrix to achieve superhydrophobicity by anchoring the long-chain organic moiety onto Cu(OH)〈sub〉2〈/sub〉 surface. Since superhydrophobic matrix is intrinsically superoleophilic, oil-infused surface is finally constructed onto stainless steel. Taking typical marine fouling organisms including sulfate-reducing bacteria (SRB) and diatoms as the representatives, oil-infused surface can steadily prevent the biofouling on stainless steel, showing the better performance than superhydrophobic surface for biofouling inhibition. Using epoxy resin as the artificial fouling agent, the pulling force to remove the glued solid on oil infused surface is much lower than that on bare stainless steel, illustrating oil layer acting as the separation cushion between fouling agent and underneath substrate.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Superhydrophobic and oil-infused surface based on prickly chestnut husk morphology Cu(OH)〈sub〉2〈/sub〉 are used as the representatives to illustrate which is the better choice to prevent marine biofouling.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718307477-ga1.jpg" width="295" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Chengyi Wang, Lin Chen, Shanshan Liu, Liang Zhu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, nitrite desorption from activated carbon fiber (ACF) in capacitive deionization (CDI) and membrane capacitive deionization (MCDI) was examined and the effects of the operation parameters (pH, voltage, temperature and flow rate) and co-existing matters were deeply investigated. Desorption mechanisms were analyzed via Brunauer–Emmett–Teller (BET) and Fourier transform infrared spectroscopy (FTIR). Results showed that the final desorption ratio increased from 0 to 100% in MCDI and the enhancement was also observed in CDI that the ratio increased from 18.7 to 83.5% when solution pH increased from 2 to 10. Increasing the voltage and solution temperature also contributed to the ion desorption both in CDI and MCDI, while the effect of flow rate was negligible. Generally, MCDI showed greater desorption performance than CDI due to the elimination of co-ions effect. However, it was interesting to find that when the voltage was in the range of 0.4-0.6 V, the desorption ratio increased from 38.4% to 50.8% in MCDI which was lower than that in CDI (45.4% to 55.8%). One possible explanation was that the presence of membranes would inevitably introduce additional resistance into the system and decrease effective voltage especially at lower voltage. Compared to the desorption performance in MCDI when the solution pH was 2, the greater desorption performance was observed in CDI which was mainly attributed to the site competition. As for the influence of coexisting matters, the presence of bovine serum albumin (BSA) posed an adverse effect for the ion desorption both in CDI and MCDI. The inhibition effect was more serious in CDI, and pore blockage caused by BSA attachment onto ACF was the main mechanism. Therefore, this study would provide some referential advice for the investigation of ion desorption in CDI and MCDI.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718312275-ga1.jpg" width="255" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 28 June 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Anwesha Sarkar, Brent S. Murray〈/p〉

Description: 〈p〉Publication date: 5 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 560〈/p〉 〈p〉Author(s): Anh-Tu Ngo, Salvatore Costanzo, Pierre-Antoine Albouy, Vincent Russier, Sawako Nakamae, Johannes Richardi, Isabelle Lisiecki〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Novel colloidal crystals made of maghemite nanocrystals are fabricated by a co-evaporation method with a mixture of ethanol/hexane. Through a series of comprehensive characterization performed by grazing incidence small-angle X-ray scattering (GISAXS) and field emission gun scanning electron microscope (FEG-SEM), we show the first example of well-defined face-centered cubic (fcc) colloidal crystals. In order to obtain a clear picture of the crystal formation, the amount of ethanol in the solution is monitored using gas chromatography. In parallel, the interactions between the nanocrystals are calculated by statistical mechanics theory using solubility parameters. Theory predicts the formation of colloidal crystals at quite high amounts of ethanol around 15%, in perfect agreement with experimental results. We show that the theory can further be applied to predict the optimal experimental conditions for the formation of colloidal crystals using other solvent mixtures.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092777571830788X-ga1.jpg" width="446" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: 20 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 559〈/p〉 〈p〉Author(s): Xiaoyu Gao, Gang Wen, Zhiguang Guo〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Based on controlling ZnO nanoarrays morphology and employing fluorine-free modification agent, superhydrophobicity in air and superoleophobicity under water were successfully achieved on the prepared cotton fabric surfaces via a two-step hydrothermal reaction. To increase adhesion between ZnO crystal layer and substrate surface, two kinds of silane coupling agents (hydrophobic TTOP-12 and hydrophilic KH550) were added selectively in the pretreatment process. The as-prepared fabric exhibited great tolerance and durableness towards external harsh environments, such as mechanical abrasion, UV radiation, immersion of acid or alkali, and high temperature. In comparison, superhydrophobic fabrics showed superior separation effect for heavy oil and water mixture, while underwater superoleophobic fabric can also show efficient separation of water and light oil with high separation efficiency and flux. In a word, heavy/light oil and water mixtures can be separated efficiently as need by choosing cotton fabrics with various wettabilities.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉The cotton fabrics with superhydrophobic and superolephobic underwater were fabricated in this paper via controlling ZnO crystal morphology and choosing various modification agents, and the results showed that they possessed efficient separations as need for oil/ water mixtures with both an efficiency and a high flux.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718311129-ga1.jpg" width="386" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Md. Obaidullah, Newaz Mohammed Bahadur, Takeshi Furusawa, Masahide Sato, Hiroshi Sakuma, Noboru Suzuki〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 nanoparticles (NPs) coated by the SiO〈sub〉2〈/sub〉 shell with a thickness up to˜6.5 nm were synthesized by a fast and facile microwave irradiation approach. The thickness of the SiO〈sub〉2〈/sub〉 shell around Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 NPs could be controlled by varying tetraethoxysilane (TEOS) concentration as well as avoiding individual SiO〈sub〉2〈/sub〉 particle formation. The synthesized Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉@SiO〈sub〉2〈/sub〉 core-shell nanocomposites (NCs) were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and energy dispersive X-ray (EDX) spectroscopy. The bigger particle size compared to the uncoated Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 NPs and Si − O–Si asymmetric stretching vibrational band at 1101 cm〈sup〉-1〈/sup〉 in the prepared NCs obtained by FE-SEM and FT-IR study, respectively anticipated the successful SiO〈sub〉2〈/sub〉 coating on Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 NPs. The presence of homogeneous silica layer was authenticated by TEM observation. The change in binding energy of Fe 2p3 and Si 2p in the synthesized NCs compared to the uncoated Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 and pure SiO〈sub〉2〈/sub〉 NPs corroborated the formation of Fe − O–Si bond at the interface of Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 (core) and SiO〈sub〉2〈/sub〉 (shell). The existence of magnetic property in the prepared NCs, even above the Curie temperature of Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉, was assured by vibrating sample magnetometer (VSM) study. This observation will undoubtedly inspire to design and fabricate novel heterostructures of iron oxide to retain its magnetization at high temperature.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719302626-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 28 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Negin Kananizadeh, Jaewoong Lee, Ehsan S. Mousavi, Keith B. Rodenhausen, Derek Sekora, Mathias Schubert, Shannon Bartelt-Hunt, Eva Schubert, Jianmin Zhang, Yusong Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Understanding the influence of surface roughness on the deposition of nanoparticles is important to a variety of environmental and industrial processes. In this work, slanted columnar thin films (SCTFs) were engineered to serve as an analogue for rough surfaces with controlled height and surface properties. The deposition of titanium dioxide nanoparticles (TiO〈sub〉2〈/sub〉NPs) onto alumina- or silica-coated SCTFs (Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-Si-SCTF, SiO〈sub〉2〈/sub〉-Si-SCTF) with varying heights (50 nm, 100 nm, and 200 nm) was measured using a combined quartz crystal microbalance with dissipation monitoring (QCM-D) and generalized ellipsometry (GE) technique. No TiO〈sub〉2〈/sub〉NP deposition was observed on flat, silica-coated QCM-D sensors or rough, 100 nm thick SiO〈sub〉2〈/sub〉-Si-SCTF. TiO〈sub〉2〈/sub〉NP deposition onto Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-Si-SCTFs in ultra-pure water was significantly higher than on the flat alumina-coated QCM-D sensor, and deposition increased as the roughness height increased. The nanoparticle attachment was sensitive to the local flow field and the interaction energy between nanoparticles and the QCM-D sensor. At a higher ionic strength condition (100 mM NaCl), TiO〈sub〉2〈/sub〉NP aggregates with varying sizes formed a rigid layer on top of SCTFs. For the first time, deposition of nanoparticles was measured as a function of roughness height, and the impact of roughness on the properties of the attached nanoparticle layers was revealed. This finding indicates that key parameters describing surface roughness should be explicitly included into models to accurately predict the transport of nanoparticles in the subsurface.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719302894-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 28 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Jean C. Villamil, Claudia M. Parra-Giraldo, León D. Pérez〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Amphotericin B (AmB) is an antifungal drug with a broad spectrum of action. It has few resistance reports, and it is widely used for treating invasive fungal infections. However, it has many drawbacks related to its administration and undesired side effects, such as nephrotoxicity. The use of polymer micelles not only increases the solubility of AmB in aqueous media, but also attenuates its toxicity. Nevertheless, polymer micelles have low loading capacities because they interact weakly with AmB, which is an amphiphilic and amphoteric molecule. In the present research, we investigate the effect of conjugating mPEG-b-PCL with cholesterol. This is a biocompatible and biodegradable block copolymer commonly used as a drug carrier. The results indicated that the presence of cholesterol increased the encapsulation efficiency and loading capacity of AmB, and improves their ability to impart controlled release. Compared with Fungizone® as reference, AmB-loaded polymer micelles presented lower 〈em〉in vitro〈/em〉 efficacy against 〈em〉Candida albicans SC5314〈/em〉, and this was seen as an increase in minimum inhibitory concentration. However, 〈em〉in vivo〈/em〉 assessment of antifungal activity using an invertebrate 〈em〉Galleria mellonella〈/em〉 model for invasive candidiasis showed comparable efficacy. The toxicity of AmB against red blood cells was attenuated upon encapsulation. The results indicated that in addition to the favourable interaction of AmB–micelle core from the presence of cholesterol, a synergistic effect was found with the segment of PCL, thereby resulting in improved performance.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719302870-ga1.jpg" width="268" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 28 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Jae Kyeong Han, Jae Yun Lee, Hyoung Jin Choi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Spinel ferrite nanoparticles with enhanced magnetism were prepared by non-stoichiometric doping of Zn cation to magnetite and adopted as an additive into carbonyl iron (CI)-based magnetorheological (MR) suspension, with the expectation of improved MR effect and suspension stability. Rheological characteristics of the MR fluids both with and without an additive were analyzed using a rotational rheometer. The addition of 0.5 wt% Zn-doped ferrite (Zn〈sub〉x〈/sub〉Fe〈sub〉3-x〈/sub〉O〈sub〉4〈/sub〉) to the MR fluid enhanced not only the MR performance but also sedimentation stability, as confirmed by Turbiscan. The nanoparticles of truncated octahedron-like shape were thought to be inserted into the free volume between microparticles.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719302857-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈p〉Non-stoichiometric Zn-doped ferrite nanoparticles were used as the additive onto CI based MR suspensions, and then their rheological and dispersive effects were investigated using a rotational rheometer and optical measurements.〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 29 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): Frank Rhein, Felix Ruß, Hermann Nirschl〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The main goal of this work is to develop and validate a new method for characterizing the material properties of hetero-agglomerates when calculating population balances in magnetic seeded filtration processes. A new approach of computing various collision cases and probabilities and then weighting the respective agglomeration rates with them is considered to be physically justifiable. An experimental design of experiment (DOE) yielded data for the variation of multiple process parameters with a reasonable standard deviation. 〈strong〉By measuring agglomeration kinetics, a deeper understanding of the process could be achieved and simple mathematical models were found in order to describe experimental data.〈/strong〉 The following multiple regression analysis showed good accordance with the agglomeration theory and thus the data was usable for further validation of the calculation results. By comparing calculated and experimental data and minimizing the residuals, estimates of the model parameters describing hard-to-measure material properties could be obtained. The comparison of experimental and computational regression models showed good agreement and thus validates the fundamental physical soundness of the implemented model. Furthermore, the comparison of the measured and calculated agglomeration kinetics further suggests the validity of the collision case model. Finally, this work showcases the possibilities of additional model calculations for a deeper, more thorough process understanding.〈/p〉〈/div〉 〈div〉 〈h6〉Graphical abstract〈/h6〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719302900-fx1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 28 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects〈/p〉 〈p〉Author(s): K. Wiercigroch-Walkosz, J. Cichos, M. Karbowiak〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The method based on the oil/water biphasic system appears as the most effective for the growth of mesoporosus silica shell on hydrophobic nanocrystals. In this paper the influence of various synthesis parameters, such as catalyst, solvent, temperature or hydrophobic chain length of surfactant, on porosity and thickness of silica layer grown on up-converting nanocrystals (UCNPs) was systematically investigated. The key factor determining morphology of silica shell and allowing to control its porosity is a kind of solvent used for TEOS dilution. For solvents of low polarity index silica shell has dendrimeric structure with pore size of 4–5.5 nm, while for solvents with high polarity index the silica shell is non-porous. The pore size can be also controlled in the range from 2 to 5.5 nm through selection the catalysts type. The morphology of the silica shell is also influenced by alkyl chain length of the cationic surfactant as well as temperature. Based on these new experimental results the mechanism of formation of mesoporous silica shell on inorganic nanopaticles was proposed and discussed. It was also proved, that the organic dyes, like Rhodamine B can be effectively incorporated inside the pores of mesoporous UCNPs@SiO〈sub〉2〈/sub〉 nanoparticles. This signify that such hybrid functional materials, which in addition exhibit stability of water dispersions and possibility of biofunctionalization, offer great potential for development of biomarkers or drug carriers.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775719300603-ga1.jpg" width="261" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉