ALBERT

Description: The article addresses the extended Graetz–Nusselt problem in finite-length microchannels for prescribed wall heat flux boundary conditions, including the effects of rarefaction, streamwise conduction, and viscous dissipation. The analytical solution proposed, valid for low-intermediate Peclet values, takes into account the presence of the thermal development region. The influence of all transport parameters (Peclet Pe, Knudsen Kn, and Brinkman Br) and geometrical parameters (entry length and microchannel aspect ratio) is investigated. Performances of different wall heat flux functions have been analyzed in terms of the averaged Nusselt number. In the absence of viscous dissipation Br=0, the best heating protocol is a decreasing wall heat flux function. In the presence of dissipation Br〉0, the best heating protocol is a uniform wall heat flux.

Description: At present, there are two main standards, ISO 23828 : 2013 and SAE J 2572–2014, which prescribe the hydrogen consumption test using the pressure method, gravimetric method, and flow method. However, these methods do not meet the test requirements for electric energy consumption and the range of plug-in hybrid fuel cell vehicles (FCVs) which are the main technical considerations in China and Europe. In this paper, a new test method for the hydrogen consumption, electric energy consumption, and range of FCVs is proposed without the use of additional hydrogen supply, measurement instruments, or energy consumption correction, which can improve the operability of the test and avoid the conversion between electric energy and hydrogen. One plug-in hybrid FCV and one nonplug-in hybrid FCV were tested using the proposed method. The results show that the new method meets the requirements of fuel economy test for FCVs with hydrogen consumption rate, electric energy consumption rate, the range for plug-in hybrid FCVs, hydrogen consumption rate, and the range for nonplug-in FCVs.

Description: The unstoppable quest for low-cost reinforcing agent gingered the enthusiasm towards developing and utilising the agro-based waste product as reinforcement since they are promptly accessible, sustainable, and inexpensive to purchase. In this study, AA6061/rice husk ash matrix composites were produced through metallurgical stir casting techniques. Different weight percentages of reinforcement in the range of 2%, 4%, 6%, and 8% were used to fabricate the composites. The reinforced composites were characterized by SEM/EDS for microstructural study. The mechanical behaviour was examined for all the produced samples. SEM/EDS analysis revealed the presence of silica, a major constituent of rice husk ash in the produced composites. The results of the mechanical behaviour show that upgrading the weight percentage of reinforcing agent increases the mechanical properties. AA6061/8% rice hush ash generated a consistent rise with filler concentration in comparison with the aluminium alloy in all operating functions.

Description: Increase in the world energy demand also increases the concentration of CO2 in the atmosphere, which contributes to global warming and ocean acidification. This study proposed the simulation process to utilize CO2 released from the acid gas removal unit in one of gas processing plants in Indonesia to enhance the production of dimethyl ether (DME) through unreacted gas recycle that can be beneficial in reducing CO2 emission to the atmosphere. Simulation was developed in Unisim R390.1 using Peng–Robinson–Stryjek–Vera (PRSV) as a fluid package. Simulation was validated by several studies conducted by many researchers and giving satisfactory results especially in terms of productivity, conversion, and selectivity as a function of reactor temperatures in the indirect and the direct DME synthesis processes. Simulation results show that the DME production was enhanced by around 49.6% and 65.1% for indirect and direct processes, respectively, at a recycling rate of 7 MMSCFD. Compressor is required to increase the unreacted gas pressure to the desired pressure in the methanol reactor or dual methanol-DME reactor in both processes. Specific power consumption (SPC) was used as a tested parameter for the effectiveness of recycling unreacted gas. Based on the simulation, the direct DME synthesis process is superior over the indirect process in terms of DME and methanol productions, SPCs, and system energy efficiencies.

Description: In this work, geopolymer synthesized with perlite and an alkaline activator medium was evaluated as a new adsorbent and photocatalyst for degradation of methylene blue (MB) dye from an aqueous medium. The functional group, the structure, and the morphology of the raw and the synthesized materials were characterized using FT-IR, XRD, and SEM analysis. The degradation of MB in the contaminated solution was examined using the spectrophotometric technique. Several analysis methods revealed the formation of the aluminosilicate gel after the geopolymerization reaction. The kinetics data with UV and without UV irradiations were well fitted with the pseudo-second-order equation. The results indicated that the degradation efficiency of cationic dye by perlite-based geopolymer without and with UV was up to 88.94% and 97.87% in 4 hours, respectively. The degradation efficiencies of methylene blue are in the following order: perlite-based geopolymer under UV irradiations is greater than perlite-based geopolymer without UV irradiations that is larger than UV irradiations. The overall experimental results suggested that the new elaborated material with synergetic adsorption and photocatalytic activities has a great potential for the treatment of water contaminated by hazardous substances.

Description: In this paper, glucosamine was produced by acid hydrolysis of five mushrooms. The glucosamine yields were investigated, and the optimum conditions were obtained as follows: acid type, sulfuric acid; acid concentration, 6 M; ratio of raw material to acid volume, 1 : 10; hydrolysis temperature, 100°C; and time, 6 h. Under these conditions, the glucosamine conversion from chitin content reached up to 92%. The results of hydrolysis kinetics indicated that hydrolysis of five mushrooms to glucosamine followed zero-order kinetics. Moreover, the relatively low activation energy for hydrolysis of straw mushroom (18.31 kJ/mol) and the highest glucosamine yield (56.8132 ± 3.5748 mg/g DM, 0.9824 g/g chitin) indicated that hydrolysis of straw mushroom was energy-saving. Thus, sulfuric acid hydrolysis of straw mushroom for glucosamine production should be considered as an efficient process for the future industrial application. However, further study is needed for glucosamine purification.

Description: In this paper, glucosamine was produced by acid hydrolysis of five mushrooms. The glucosamine yields were investigated, and the optimum conditions were obtained as follows: acid type, sulfuric acid; acid concentration, 6 M; ratio of raw material to acid volume, 1 : 10; hydrolysis temperature, 100°C; and time, 6 h. Under these conditions, the glucosamine conversion from chitin content reached up to 92%. The results of hydrolysis kinetics indicated that hydrolysis of five mushrooms to glucosamine followed zero-order kinetics. Moreover, the relatively low activation energy for hydrolysis of straw mushroom (18.31 kJ/mol) and the highest glucosamine yield (56.8132 ± 3.5748 mg/g DM, 0.9824 g/g chitin) indicated that hydrolysis of straw mushroom was energy-saving. Thus, sulfuric acid hydrolysis of straw mushroom for glucosamine production should be considered as an efficient process for the future industrial application. However, further study is needed for glucosamine purification.

Description: Background. This paper investigated the effectiveness of lime treatment and subsequent acid precipitation (using H2SO4) as a pretreatment of partially stabilised leachate. This study obtained high removal efficiencies (〉70%) from the lime and acid pretreated partially stabilised leachate. The treatment of this wastewater with 10 g/L dosage of optimum lime (pH 12) at 25°C had led to the 41% COD elimination in the initial stages of pretreatment. Subsequent pH adjustment using 1 N sulfuric acid and granular-activated carbon adsorption in general revealed more than 92% removal of the 4 g/L of carbon dosage. Therefore, the results revealed that the adsorption of COD on the GAC stemmed from the kinetics rate of the pseudo-second-order.

Description: Mn (II)/AC adsorbents were prepared by ultrasonic impregnation. The 2 wt. % Mn/AC showed best adsorptive performance, and the optimal adsorption temperature was 313 K. Benzene, methylbenzene, and naphthalene were used to explore the adsorptive selectivity of Mn/AC, indicating that Mn could enhance the adsorptive capacity but could not improve the adsorptive selectivity. The adsorptive mechanism was mostly like to be π-complex. Adsorptive isotherms and kinetics were investigated, and the parameters were calculated. The R2, RMSE, and AICc were used to assess the optimal model. The results showed that Temkin adsorptive isotherm was more suitable to describe the isothermal data; the MPnO kinetics model was more superior to other kinetic models. The order of reaction was between 1 and 2. The outcome of adsorptive thermodynamics indicated that removal of DBT onto Mn/AC was a spontaneous and exothermic process.

Description: Wax deposition from crude oil that blocks the pipeline and increases the viscosity of the fluid is considered as a serious challenge for petroleum transportation. Employment of chemical additives, the so-called pour point depressants (PPDs), is widely used to solve this problem. Among them are the ethylene-vinyl acetate (EVA) copolymers (EVAc), containing a polyethylene segment along the backbone with vinyl acetate. To improve the performance of EVAc as PPD, the compositions of this polymer with crude gossypol (CG), isolated from the refined cottonseed oil soapstock, were prepared by joint milling in a ball mill. Prepared compositions were characterized by Fourier transform infrared (FTIR), ultraviolet (UV), and nuclear magnetic resonance (NMR) spectroscopy. The pour point and viscosity of the crude oil from the Akshabulak oil field (Kazakhstan) were studied. The compositions with 10, 20, and 25 wt% of CG demonstrate better efficiency as PPD for crude oil than EVAc at the dosage of PPD of 50, 100, 250, and 500 ppm. The improved properties of the obtained PPD in comparison with the commercial EVAc is explained by the appearance of additional nonpolar and polar groups caused by the formation of the EVAc/CG composition.

Description: The removal of brilliant green (BG) dye from an aqueous solution using activated carbon (AC) derived from guava tree wood is conducted in batch conditions. The influence of different factors such as contact time, pH, adsorbent dosage, initial dye concentration, and temperature on the adsorption of BG onto AC was investigated. FTIR, BET, and SEM analyses were performed to determine the characteristics of the material. The isotherm results were analyzed using the Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherms. Linear regression was used to fit the experimental data. It was found that the equilibrium data are best represented by the Freundlich isotherm, and the adsorption capacity (qe) was 90 mg dye/g AC. The values of the free energy (∆G), enthalpy (∆H), and entropy (∆S) were −86.188 kJ/mol, 43.025 kJ/mol, and 128 J/mol.K, respectively, at pH 7 for the BG dye. The kinetics of BG dye adsorption were analyzed using pseudo-first-order and pseudo-second-order models, and it was found that the pseudo-second-order model was suitable for the behavior of the BG dye at R2 = 0.999.

Description: 5-Hydroxymethylfurfural as a versatile organic compound is considered as a promising biomass-derived product via hydrolysis followed by dehydration of lignocellulosic biomass using solid catalysts. In this study, lignocellulosic materials (corncob) were utilized to synthesize 5-hydroxymethylfurfural via solid acid catalytic conversion. The precursor of the catalyst material was chemically impregnated with ZnCl2 prior to carbonization. The solid catalyst was prepared with three different acid concentrations of 98%, 96%, and 94% of sulfuric acid. The prepared catalyst was characterized by acid density elemental analysis, FTIR, XRD, and SEM. The maximum result of the total acid density and amount of SO3H group was recorded as 3.5 mmol/g and 0.61 mmol/g, respectively, with high sulfur content of 1.87%. The result from FTIR spectra of BC-SO3H−1 confirms the incorporation of -SO3H groups into the carbon material. BC-SO3H−1 was selected based on the acid density and elemental analysis of the catalyst. The activity of the selected catalyst (BC-SO3H−1) was studied on the transformation of corncob to 5-hydroxymethylfurfural using biphasic solvent (water: ethyl acetate) and NaCl in the reaction medium. The intermediate result in the hydrolysisdehydration reaction was analyzed using FTIR and the functional groups observed confirm the occurrence of 5-HMF in the intermediate reaction result.

Description: In this study, mixed oxides of Mn-Cu and Fe-Cu on OMS-2 support having an octahedral structure were synthesized by the refluxing and impregnation methods. The characteristics of the materials were analyzed by XRD, FTIR, SEM, EDX, and H2-TPR. In the CO oxidation test, CuFeOx/OMS-2 had slightly higher catalytic activity but is significantly more stable than CuMnOx/OMS-2 and CuO/OMS-2. Due to its lower reduction temperature in H2-TPR analysis, the Mars-Van-Krevelen mechanism for CuFeOx/OMS-2 (Cu2+–O–Fe3+ ↔ Cu+–□–Fe2+) could take place more energetically than CuO/OMS-2 and CuMnOx/OMS-2 (Cu2+–O2−–Mn4+ ↔ Cu+–□–Mn3+). In addition, the interaction between Fe and Cu in the catalyst could improve the durability of the surface oxides structure in comparison with that between Mn and Cu. With the high specific rate and TOF of 28.6 mmol/h.g and 0.508, respectively, CuFeOx/OMS-2 has a great potential as an effective catalyst for low-temperature oxidation application in CO and possible VOCs removal.

Description: This paper carried out the study on removal of ammonium from aqueous solutions by zeolite derived from electrolytic manganese residue (EMR) via a fusion method. The variables of pH, contact time, EMRZ (EMR-based zeolite) dosage, initial ammonium concentration, and competitive cations and anions on the ammonium uptake capacity were systematically investigated in an attempt to illustrate adsorption performance of EMRZ. The results show that these influence factors had a remarkable impact on the ammonium uptake capacity of EMRZ. Maximum ammonium uptake capacity was achieved at pH value 8.0, EMRZ dosage 0.2 g/100 mL, contact time 100 min, initial ammonium concentration 200 mg/L, and temperature 35°C. Under optimized conditions, ammonium uptake capacity onto EMRZ was up to 27.89 mg/g. The competitive degree of cations in ammonium adsorption process follows the sequence of Na+〉K+〉Ca2+〉Mg2+, and the sequence of anion effect on ammonium removal onto EMRZ is CO32− 〉 Cl− 〉 SO42− 〉 PO43−. The adsorption kinetic was explored and best represented by pseudo-second-order kinetic model. And the adsorption isotherm experimental data had best fitness with the Freundlich and Koble–Corrigan model, suggesting that heterogeneous uptake was the principal mechanism adopted in the process of ammonium adsorption. Moreover, calculation of thermodynamic parameters such as change in free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) was carried out and it was determined to be −15.77∼−14.03 kJ·mol−1, +37.66 kJ·mol−1, and +173.38 J·mol−1·K−1, respectively. These parameters confirmed that ammonium uptake onto EMRZ was an endothermic and spontaneous process. Moreover, no obvious deterioration tendency was observed for the regenerated EMRZ compared with fresh EMRZ. These results indicate that EMRZ has wide application prospects in removing ammonium from wastewater.

Description: In the petroleum industry, the researchers have developed a new technique called enhanced oil recovery to recover the remaining oil in reservoirs. Some reservoirs are very complex and require advanced enhanced oil recovery (EOR) techniques containing new materials and additives in order to produce maximum oil in economic and environmental friendly manners. In this work, the effects of nanosuspensions (KY-200) and polymer gel HPAM (854) on oil recovery and water cut were studied in the view of EOR techniques and their results were compared. The mechanism of nanosuspensions transportation through the sand pack was also discussed. The adopted methodology involved the preparation of gel, viscosity test, and core flooding experiments. The optimum concentration of nanosuspensions after viscosity tests was used for displacement experiments and 3 wt % concentration of nanosuspensions amplified the oil recovery. In addition, high concentration leads to more agglomeration; thus, high core plugging takes place and diverts the fluid flow towards unswept zones to push more oil to produce and decrease the water cut. Experimental results indicate that nanosuspensions have the ability to plug the thief zones of water channeling and can divert the fluid flow towards unswept zones to recover the remaining oil from the reservoir excessively rather than the normal polymer gel flooding. The injection pressure was observed higher during nanosuspension injection than polymer gel injection. The oil recovery was achieved by about 41.04% from nanosuspensions, that is, 14.09% higher than polymer gel. Further investigations are required in the field of nanoparticles applications in enhanced oil recovery to meet the world's energy demands.

Description: High temperature is the main factor responsible for degrading the lubrication and antiwear properties of aero-lubricating oils. Accordingly, this study assessed the effects of thermal treatment of diester aviation lubricating oil and the associated mechanism. Fourier-transform infrared spectroscopy and gas chromatography/mass spectrometry analyses showed that low-molecular-weight compounds, such as monoesters, diesters, alcohols, and olefins, were the primary degradation products. An assessment of the degradation mechanism of bis(2-ethylhexyl)decanedioate showed that pyrolysis, resulting in the cleavage of β-C–H and C–C bonds, was the main process involved. Additional investigation using advanced polymer chromatography showed that the molecular weights of oil samples changed slightly at high temperatures, while the viscosity and viscosity-temperature index values were relatively stable. High-pressure differential scanning calorimetry established that the thermal oxidation stability of these oils decreased above 250°C. Finally, variations in the chemical compositions of the oil samples were found to be highly correlated with changes in physicochemical properties during thermal processing, with the formation of low-molecular-weight polar compounds greatly increasing the acid numbers of the oils.

Description: In this paper, green and facile synthesis of sulfur- and nitrogen-codoped carbon nanospheres (CNs) was prepared from the extract of Hibiscus sabdariffa L by a direct hydrothermal method. Finally, sulfur-carbon nanospheres (CNs) were used as the adsorbent to remove Pb+2 ions from aqueous solutions because of the high surface area of S-CNs from CNs and N-CNs. The synthesized nanospheres were examined by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy, transmission electron microscopy (TEM), and nitrogen adsorption-desorption isotherms. The results show spherical shapes have a particle size of up to 65 nm with a high surface area capable of absorbing lead ions efficiently. Additionally, the factors affecting the process of adsorption that include equilibrium time, temperature, pH solution, ionic intensity, and adsorbent dose were studied. The equilibrium removal efficiency was studied employing Langmuir, Freundlich, and Temkin isotherm forms. The kinetic data were analyzed with two different kinetic models, and both apply to the adsorption process depending on the values of correlation coefficients. The thermodynamic parameters including Gibbs free energy (ΔG°), standard enthalpy change (ΔH°), and standard entropy change (ΔS°) were calculated for the adsorption process.

Description: Fly ash, a waste product from thermal power plants, is one of the good alternatives for use as a filler in polymers, especially in flame retardants. Fly ash is an environmentally friendly fire retardant additive for composites, used in place of conventional flame retardant additives such as halogenated organic compounds, thus promoting environmental safety. In this study, fly ash was modified with stearic acid to improve adhesion at the polymers interface and increase compatibility. Fly ash was studied at various volumes (5, 10, and 20 wt.% fly ash) used in this study to synthesize fly ash-epoxy composites. The results show that the tensile strength, flexural strength, compressive strength, and impact strength of these synthetic materials increase when fly ash is modified to the surface, compressive strength: 197.87 MPa, flexural strength: 75.20 MPa, impact resistance: 5.77 KJ/m2, and tensile strength: 47.89 MPa. Especially, the fire retardant properties are improved at a high level, with a modified 20% fly ash content: the burning rate of 16.78 mm/min, minimum oxygen index of 23.2%, and meet the fire protection standard according to UL 94HB with a burning rate of 8.09 mm/min. Scanning electron microscopy (SEM) and infrared spectroscopy were used to analyze the morphological structure of fly ash after being modified and chemically bonded with epoxy resin background.

Description: Increase in the world energy demand also increases the concentration of CO2 in the atmosphere, which contributes to global warming and ocean acidification. This study proposed the simulation process to utilize CO2 released from the acid gas removal unit in one of gas processing plants in Indonesia to enhance the production of dimethyl ether (DME) through unreacted gas recycle that can be beneficial in reducing CO2 emission to the atmosphere. Simulation was developed in Unisim R390.1 using Peng–Robinson–Stryjek–Vera (PRSV) as a fluid package. Simulation was validated by several studies conducted by many researchers and giving satisfactory results especially in terms of productivity, conversion, and selectivity as a function of reactor temperatures in the indirect and the direct DME synthesis processes. Simulation results show that the DME production was enhanced by around 49.6% and 65.1% for indirect and direct processes, respectively, at a recycling rate of 7 MMSCFD. Compressor is required to increase the unreacted gas pressure to the desired pressure in the methanol reactor or dual methanol-DME reactor in both processes. Specific power consumption (SPC) was used as a tested parameter for the effectiveness of recycling unreacted gas. Based on the simulation, the direct DME synthesis process is superior over the indirect process in terms of DME and methanol productions, SPCs, and system energy efficiencies.

Description: In this work, geopolymer synthesized with perlite and an alkaline activator medium was evaluated as a new adsorbent and photocatalyst for degradation of methylene blue (MB) dye from an aqueous medium. The functional group, the structure, and the morphology of the raw and the synthesized materials were characterized using FT-IR, XRD, and SEM analysis. The degradation of MB in the contaminated solution was examined using the spectrophotometric technique. Several analysis methods revealed the formation of the aluminosilicate gel after the geopolymerization reaction. The kinetics data with UV and without UV irradiations were well fitted with the pseudo-second-order equation. The results indicated that the degradation efficiency of cationic dye by perlite-based geopolymer without and with UV was up to 88.94% and 97.87% in 4 hours, respectively. The degradation efficiencies of methylene blue are in the following order: perlite-based geopolymer under UV irradiations is greater than perlite-based geopolymer without UV irradiations that is larger than UV irradiations. The overall experimental results suggested that the new elaborated material with synergetic adsorption and photocatalytic activities has a great potential for the treatment of water contaminated by hazardous substances.

Description: This study investigated the potential of the bacterium Stenotrophomonas maltophilia UCP 1601 to produce a new biomolecule with emulsifying properties by determining the hemolytic activity, obtaining a halo of 9 mm in blood agar. Fermentations were carried out in saline mineral medium supplemented with 10% waste soybean oil (WSO) and different concentrations of glucose, peptone, ZnCl2, and MgSO4, according to a 24 full-factorial design. The results showed that the best results were obtained in condition 6 (medium composed of 4% glucose, 1% peptone, 2.72% ZnCl2, and 2.46% MgSO4), with excellent high emulsification index of 82.74%, using burned motor oil. The emulsifying property of the biomolecule produced was confirmed by the emulsification index of 78.57, 54.07, and 58.62%, using soybean, corn, and diesel oils, respectively, and the stability at different values of pH, temperature, and NaCl concentrations. The yield of the produced bioemulsifier was 2.8 g/L, presenting an anionic character and polymeric nature (37.6% lipids, 28.2% proteins, and 14.7% carbohydrates), confirmed by FTIR. The new bioemulsifier demonstrated promising potential for bioremediation of hydrophobic contaminants in the environment, since it had the ability to reduce the viscosity of WSO and burned motor oil, as well as excellent dispersion capacity of the burned motor oil in water (69.94 cm2 of oil displacement area), and removing 71.7% of this petroleum derivative from sandy soil.

Description: In this paper, glucosamine was produced by acid hydrolysis of five mushrooms. The glucosamine yields were investigated, and the optimum conditions were obtained as follows: acid type, sulfuric acid; acid concentration, 6 M; ratio of raw material to acid volume, 1 : 10; hydrolysis temperature, 100°C; and time, 6 h. Under these conditions, the glucosamine conversion from chitin content reached up to 92%. The results of hydrolysis kinetics indicated that hydrolysis of five mushrooms to glucosamine followed zero-order kinetics. Moreover, the relatively low activation energy for hydrolysis of straw mushroom (18.31 kJ/mol) and the highest glucosamine yield (56.8132 ± 3.5748 mg/g DM, 0.9824 g/g chitin) indicated that hydrolysis of straw mushroom was energy-saving. Thus, sulfuric acid hydrolysis of straw mushroom for glucosamine production should be considered as an efficient process for the future industrial application. However, further study is needed for glucosamine purification.

Description: Nowadays water bodies across the world are heavily polluted due to uncontrollable contamination of heavy metal particles, toxic dyes, and other harmful wastes discharged by emerging industries other than normal domestic wastages. This contamination needs sufficient control to protect the natural water bodies. There are various methodologies to be followed to perform wastewater treatment, in which the adsorption method of filtration is found to be efficient. The adsorption method is a high priority and preferable filtration method compared to other waste water treatment methods due to its peculiar characteristics. Considering the adsorption method, there are multiple options available in selecting material and methodology for the filtration process. In selecting the filtering material, there is much attraction towards graphene and its oxides, which have widespread range of differential applications in commercial industries because of their eco-friendly characteristic features. The importance of various graphene composites and their chemical properties is found to be significant in various fields. Analyzing the adsorbing properties of graphene widely, this article deeply reviews about the improvements and the technologies identified for using graphene and (GO) graphene oxide in wastewater treatment taken into discussion elaborately. Therefore, in this hard review, the advantages and demerits of using graphene for wastewater treatment as well as improving its properties to make it more suitable for wastewater treatment are detailed.

Description: A three-dimensional computational fluid dynamics (CFD) study was carried out for drilling fluid flow with drill cuttings in open channels. The flow is similar to the return flow when drilling, stream containing drilling fluid, and drill cuttings. The computational model is under the framework of the Eulerian multifluid volume of the fluid model. The Herschel–Bulkley rheological model was used to describe the non-Newtonian rheology of the drilling fluid, and the computational model was validated with experimental results for two-phase flow in the literature. The effect of flow depth and flow velocity in an open channel was studied for drill cutting size of up to 5 mm and for a solid volume fraction of up to 10%. For constant cross section and short open channels, the effect of drill cuttings on flow depth and mean velocity was found to be small for particle sizes less than 5 mm and solid volume fractions less than 10%. High momentum force in the downward direction can carry the solid-liquid mixture at higher velocities than a lower density mixture. Higher inclination angles mean that the gravity effect upon the flow direction is more significant than the particle friction for short channels.

Description: One of the main sources of activated carbon is biomass which can be transformed into char by pyrolysis. Apart from the obtaining coal, the pyrolysis of biomass can be used for the preparation of fuels, and this is why it is very important to determine its kinetic parameters for modelling. In the present research, the pyrolysis enthalpy of palm nut shells (Elaeis guineensis) was determined with the use of a differential scanning calorimetry study (DSC). To determine the kinetic parameters, the Not Reacted Core model was employed. This model considers that there is a heat and mass gradient between the furnace atmosphere and the interface formed during pyrolysis. To obtain the required data for the model, palm nut shells were submitted to pyrolysis in a Nichols furnace under reducing atmosphere. Samples were taken every 10 minutes to calculate char conversion. The experimental pyrolysis enthalpy resulted to be 301.81 J/g and then the monomeric units of cellulose, hemicellulose, and lignin were employed in order to determine the pyrolysis enthalpy per mole. The three biopolymers react with different mechanisms at different temperatures. The molecular weight resulted to be 172.38 g/mole, and the enthalpy for pyrolysis was 52.03 kJ/mol. For the application of the Not Reacted Core model, the amorphous char heat transfer coefficient was selected, and the value is 1.6 J/s·m·K. The reaction rate constant was 6.64 × 10−9 1/s assuming a first-order reaction, whereas the effective diffusion across the char layer was 4.83 × 10−7 m2/s.

Description: The qualitative and quantitative determination of the components of textile fibers takes an important position in quality control. A fast and nondestructive method of simultaneously analyzing four fiber components in blended fabrics was studied by near-infrared (NIR) spectroscopy combined with multivariate calibration. Two sample sets including 39 and 25 samples were designed by simplex mixture lattice design methods and used for experiment. Four components include wool, polyester, polyacrylonitrile, and nylon and their mixture is one of the most popular formulas of textiles. Uninformative variable elimination-partial least squares (UVEPLS) and the full-spectrum partial least squares (PLS) were used as the tool. On the test set, the mean standard error of prediction (SEP) and the mean ratio of the standard deviation of the response variable and SEP (RPD) of the full-spectrum PLS model and UVEPLS model were 0.38, 0.32 and 7.6, 8.3, respectively. This result reveals that the UVEPLS can construct local models with acceptable and better performance than the full-spectrum PLS. It indicates that this method is valuable for nondestructive analysis in the field of wool content detection since it can avoid time-consuming, costly, and laborious wet chemical analysis.

Description: In this study, a nonisothermal kinetics analysis of petcoke was performed at heating rates of 10, 15, and 20°C/min using thermal gravimetric analysis (TGA). The behaviour of petcoke at different gasification stages (dewatering, volatilization, char burning, and burnout) was studied. The effect of heating rate on the activation energy of petcoke gasification was also investigated. The activation energy of petcoke was estimated using different kinetic models that include volume reaction model (VRM), shrinking core model (SCM), random pore model (RPM), Coats and Redfern model (CRM), and normal distribution function (NDF). The NDF model was modified in this study. It was found that the experimental data were best fitted with the modified normal distribution function (MNDF) and SCM. The results also showed that activation energy decreases as heating rate increases, leading to reduction in gasification completion time.

Description: Nowadays, biomass has been employed to prepare biosorbents for heavy metals uptake; however, further disposal of polluted material has limited its application. In this work, nickel and lead removal was performed using yam peels and the resulting polluted biomass was mixed with concrete to produce bricks. The biomass was characterized by FT-IR analysis for testing functional groups diversification before and after adsorption process. The effect of adsorbent dosage, temperature, and initial solution concentration was evaluated to select suitable values of these parameters. Adsorption results were adjusted to kinetic and isotherm models to determine adsorption mechanism. Desorption experiments were also performed to determine the appropriate desorbing agent as well as its concentration. Immobilization technique of cement-based solidification/stabilization was applied and the polluted biomass was incorporated to concrete bricks at 5 and 10%. Mechanical resistance and leaching tests were carried out to analyze the suitability of heavy metals immobilization. The suitable values for dosage, temperature, and initial solution concentration were 0.5 g/L, 40°C and 100 ppm, respectively. The kinetic model that best fitted experimental results was pseudo-second order indicating a dominant physicochemical interaction between the two phases. The highest desorption yields were found in 52.47 and 74.84% for nickel and lead ions. The concrete bricks exhibited compression resistance above 5 MPa and all the leachate reported concentrations below the environmental limit. These results suggested that nickel and lead immobilization using concrete bricks is a good alternative to meet disposal problems of contaminated biomass.

Description: In this paper, the results of the study on the influence of the addition of 10 wt.% of FeCl3, CoCl2, NiCl2, ZnCl2, SnCl2, and CuCl2 on the wheat straw pyrolysis process are presented. The studied chlorides were found to affect the pyrolysis process; however, the highest activity was observed while using CuCl2. The presence of the copper chloride led to the decrease in the temperature of the initial destruction of hemicellulose fraction of wheat straw by 64°С. Besides, the use of CuCl2 allowed increasing the yield of liquid and solid pyrolysis products as well as decreasing the molecular weight distribution of the volatiles. Moreover, the increase in the hydrogen and decrease in carbon dioxide concentration were also observed in the presence of copper chloride. The analysis of the solid residue obtained in the wheat straw pyrolysis in the presence of CuCl2 showed the increase in the specific surface area of the carbon residue from 24 up to 63.5 m2/g in comparison with that obtained for the noncatalytic process.

Description: The process simulation performed in the present study aimed at investigating energetically self-sufficient wastewater treatment plant of 500,000 population equivalents. To implement this, three different scenarios were evaluated using computational tools named GPS-X® and SuperPro®. They were designed based on municipal wastes recovery to energy generation and its utilisation within the facility. An anaerobic/anoxic/oxic process for biological treatment of wastewater was considered and mesophilic anaerobic digestion at different scenarios (1) primary sludge (PS) with waste activated sludge (WAS), (2) PS with thermally hydrolysed WAS, and (3) PS with WAS and organic fractions derived from municipal solid waste. The results from scenario 1 and scenario 2 showed only enough thermal energy to meet their demand (they reach only 44 and 52% of electrical self-sufficiency, respectively), while positive net thermal and electrical energy result in scenario 3 from codigestion of sewage sludge and the organic fraction of municipal solid waste. The main limitation of tools used is their lack of sensitivity to economies of scale and their dependence on real data used for process design to obtain more accurate results.

Description: Biodiesel is the best candidate for fuel oil replacement, and to obtain it, heterogeneous catalysts offer large advantages: they can be separated from the product and reused. This work reviews a novel one-step synthesis of CaO-ZnO catalytic particles suitable for biodiesel production. The catalyst is synthesized using an original simple method that involves mixing of ZnO with CaCO3 and subsequent calcination. The CaO-ZnO microparticles obtained present an average size of 2 μm. This material shows the characteristic crystallographic cubic structure of CaO and the hexagonal phase of ZnO. The temperature-programmed reduction experiment evidences an interaction between CaO and ZnO. Moreover, the infrared spectroscopy shows typical bands of these compounds. The catalyst shows high biodiesel yield, up to 73% in the first cycle and 64% in the second one. In this work, the synthesis of an efficient CaO-ZnO catalyst with a huge potential is revealed, which could be an economic alternative to produce biodiesel.

Description: Chrysoidine is a type of industrial azo dye and a well-known toxicant. Due to its good dyeing characteristics, it is widely used for dyeing leather, paper, feather, grass, wood, bamboo, etc. Hence, it is very important to remove or reduce its concentration below the contamination level in the waste line by using low-cost technologies. Sawdust is a plentiful material available very cheaply from sawmills and woodworks. Therefore, the present work was conducted to study sorption ability of both raw sawdust and chemically activated sawdust carbon on the removal of chrysoidine from the aqueous solutions. Adsorption isotherms of the dye on sawdust were determined and correlated with usual isotherm equations like Freundlich and Langmuir. Experimental results have shown that sawdust has a high adsorption efficiency, and the adsorption of chrysoidine followed Freundlich’s isotherm. Although raw sawdust proved to be slightly less efficient in comparison to chemically treated sawdust but in economic terms, raw sawdust is more cost-effective as the difference in the percent dye removal is less than the difference in the manufacturing costs. The influence of several parameters such as effect of temperature, adsorbent dose, adsorption time, etc., on the adsorption process was studied along with thermodynamic parameters such as enthalpy (ΔH°) and entropy (ΔS°).

Description: The wastewater from industrial laundries has a high quantity of contaminants from the washing process, as well as chemical additives. Aiming at the treatment of this type of wastewater, the present study evaluated the performance of a combined coagulation/flocculation/sedimentation process (C/F/S) and membrane separation to treat laundry wastewater in relation to physicochemical parameters of water quality. For this purpose, a Doehlert experimental design was applied to the C/F/S step using the natural coagulant Tanfloc POP® with maximum color and turbidity removal efficiency obtained of 80.27% and 86.50%, respectively, under conditions of pH of 6.4 and a coagulant concentration of 110 mg·L−1. The supernatant from the C/F/S step was used in the sequential microfiltration (MF) and ultrafiltration (UF) experiments. The maximum values of color, total nitrogen, dissolved solids, and turbidity removal were similar to MF and UF membranes at transmembrane pressure of 1.4 bar, with the greatest flow of permeates (92.2 L·h−1·m−2) presented by the MF membrane at 1.4 bar. The total efficiency of the combined C/F/S-MF process indicated the quality of the treated wastewater since it reduced 98.4% of the color, 99.1% of turbidity, 71.7% of the surfactants, and more than 55% of the total dissolved solids (TDS), chemical oxygen demand (COD), and total organic carbon (TOC) from the industrial laundry wastewater. This study showed that the C/F/S-MF combined process could be an efficient treatment of laundry wastewater.

Description: Differences in morphology, pH, and electric charge of chitosan (CS) based hydrogels prepared by complexation with carboxymethylcellulose (CMC), carboxymethylated starch (CMS), and alginic acid (AA) at different polymers ratios and changing the order of addition were studied. CMC/CS and AA/CS hydrogels were amorphous and porous three-dimensional networks, with smaller pores at higher anionic polymer/CS ratios. Gelation time increased the agglomeration in the case of CMC/CS and CMS/CS gels. CMC/CS gels showed negative zeta potential values around −372 mV to −51 mV and CMS/CS gels in the range of −526 mV and −158 mV.

Description: This research describes the photocatalytic design for oil removal from produced water. It involves batch and continuous processes. The photocatalytic degradation of oil has been conducted in glass reactors. The effects of nano-TiO2 concentration, the number of lamps, and the time of radiation were studied in the batch system, while in the continuous treatment, the number of lamps, the direction of light radiation, and the time of processes were studied. The results showed that all the oil was removed in the batch system and the maximum percentage of oil removal was 71% in the continuous system.

Description: The present study is aimed at using one of the most promising methods called reactive extraction to extract succinic acid from aqueous solution by using N,N-dioctyloctan-1-amine in biodiesel as diluent made from sunflower oil, rice bran oil, sesame oil, and karanji oil. The results of extraction studies with the diluents (physical) showed their inability to recover any acid by themselves. In reactive extraction, the organic phase extracting power solely depends on tri-n-octylamine. The ranges of the distribution coefficient are found as 7.62–18.12 for sunflower oil biodiesel, 8.33–17.45 for rice bran oil biodiesel, 7.0–17.67 for sesame oil biodiesel, and 9.85–21.36 for karanji oil biodiesel. The ranges of the loading ratio are 0.1–3.0 for sunflower oil biodiesel, 0.1–2.9 for rice bran oil biodiesel, 0.2–2.9 for sesame oil biodiesel, and 0.1–2.9 for karanji oil biodiesel. The karanji and sunflower oil showed higher values of distribution coefficient (KD) over rice bran oil and sesame oil which might be due to presence of both C20 and special fatty acids. The results show that biogenous diluents along with N,N-dioctyloctan-1-amine as extractant form a nontoxic and viable option for the extraction of succinic acid in the binary phase system.

Description: This study provided a basis for new possibilities concerning the use of the sugarcane bagasse ash as a green pozzolanic addition to the Portland cement composite. To that effect, a simple micronization method using air jet milling without any other additional thermal procedure was used to control the characteristics of ash particles. This procedure not only maintains the required characteristics of the residues but can also improve some of them. Sugarcane bagasse ash is a residue produced on large scale in Brazil by ethanol and sugar plants as a result of the burning of sugarcane bagasse in energy cogeneration. The residue used in this study was initially characterized by scanning electron microscopy, granulometric and specific mass analyses, N2 adsorption measurements, X-ray diffraction, X-ray fluorescence spectroscopy, and thermogravimetric analysis with differential thermal analysis. Pozzolanic ash activity was evaluated according to the axial compressive strength at 28 days and the modified Chapelle methods. The results showed that the milling fly sugarcane bagasse ash samples presented satisfactory pozzolanic activity.

Description: This article details an investigation on the mechanism of corrosion inhibition of mild steel using amylose-acetate-blended carboxymethyl chitosan (AA-CMCh) in acidic media in the context of kinetic and thermodynamic parameters. The surface of mild steel was exposed to test solutions and evaluated using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The activation energy (Ea), free energy of adsorption (ΔG), enthalpy of activation (ΔHads), and entropy of activation (ΔSads) were determined in order to elucidate the mechanism of corrosion inhibition. The results confirmed that AA could be improved using CMCh as a corrosion inhibitor. The corrosion rate decreased from 1109.00 to 229.70 mdd (79.29%), while corrosion inhibition increased from 35.13 to 89.72%. Sulfate acid (H2SO4) of 0.25 M also helped in decreasing the corrosion rate from 2664.4 to 1041.67 mdd (60.9%) while also in increasing corrosion inhibition from 56.94 to 68.31%. The calculated values for ΔG, ΔHads, and ΔSads were −33.22 kJ·mol−1, −48.56 kJ·mol−1, and 0.0495 kJ·mol−1·K−1, respectively. The mechanism of corrosion inhibition of mild steel in the acidic condition is dominated and precipitated by the formation of the Fe-chelate compound, which was confirmed by the SEM/EDS spectrum. The reactions were spontaneous, exothermic, and irregular and takes place on the surface of mild steel.

Description: This work investigated the use of waste tire as a source of carbon in preparation of carbon-based catalysts for applying in ethanol dehydration. The pyrolysis of waste tire was performed to obtain the solid carbon, and then it was treated with two different acids including HCl and HNO3 prior to the activation process with different temperatures to gain suitable carbon catalysts. All carbon catalysts were characterized using nitrogen physisorption, XRD, FTIR, and acid-base titration. The catalysts were tested for catalytic ethanol dehydration in a micropacked-bed reactor under the temperature range from 200°C to 400°C. It revealed that the ethanol conversion increased with increasing the reaction temperature for all catalysts. The carbon catalyst treated with HCl and calcined at 420°C (AC_H420) exhibited the highest ethanol conversion of 36.2% at 400°C having ethylene and diethyl ether selectivity of 65.9 and 33.5%, respectively. The high activity of this catalyst can be attributed to the high acid density at the surface (18.5 μmol/m2), which was significantly higher than those of most other catalysts (less than 8.0 μmol/m2).

Description: Over the years, the organosolv pulping process has proven to be a valuable pretreatment method for various lignocellulosic feedstocks. The objective of this study was to characterize and assess the potential applicability of the organosolv lignin fraction from European larch sawdust, as no research has been conducted in this field so far. Eight different samples were prepared from the European larch sawdust under varied reaction conditions and one milled wood lignin sample as reference. The reaction temperature and sulfuric acid loading were varied between 420 and 460 K and 0.00 and 1.10% (w/w on dry wood basis) H2SO4, respectively. The antiradical potential (via DPPH• method), chemical structure (via ATR-FTIR, 1H NMR, 31P NMR, and thioacidolysis), as well as the molecular weight distribution of the isolated lignins were analyzed and compared. Results from thioacidolysis show a direct correlation between the amount of β-ether bonds broken and pulping process severity. Similarly, both antiradical potential and phenolic hydroxyl group content exhibit a direct relationship to reaction temperature and catalyst loading. On the contrary, the content of aliphatic hydroxyl groups and the average molecular weights both decreased with increasing process severity. The high content of phenolic hydroxyl groups and antioxidative potential of the larch organosolv fractions, especially for the sample isolated at 460 K and 1.10% H2SO4 loading, indicate good applicability as antioxidants as well as feedstocks for further downstream valorization and require additional research in this area.

Description: Estimation of pressure losses and deposition velocities is vital in the hydraulic design of annular drill holes in the petroleum industry. The present study investigates the effects of fluid velocity, fluid type, particle size, particle concentration, drill string rotational speed, and eccentricity on pressure losses and settling conditions using computational fluid dynamics (CFD). Eccentricity of the drill pipe is varied in the range of 0–75%, and it rotates about its own axis at 0–150 rpm. The diameter ratio of the simulated drill hole is 0.56. Experimental data confirmed the validity of current CFD model developed using ANSYS 16.2 platform.

Description: Flow visualization experiments are carried out to study the flow regimes and breakup length of the water sheet generated by two impinging liquid jets from an atomizer made of two identical tubes 0.686 mm in diameter. These experiments cover liquid jet Reynolds numbers based on the pipe diameter in the range of 1541 to 5394. The effects of the jet velocities and impingement angle between the two jets on the breakup performance are studied. Four spray patterns are recognized, which are presheet formation, smooth sheet, ruffled sheet, and open-rim sheet regimes. Water sheet breakup length is found to be consistent with previous experimental and theoretical results in the lower Weber number (based on water jet diameter and velocity) range. In the relatively high Weber number range, the breakup length tends to a constant value with increasing Weber number, and some discrepancies between experimental and theoretical predictions do exist. Measured water sheet area increases with increasing liquid jet Reynolds numbers and impingement angle within the range of the current study.

Description: Although the exposure of polymeric materials to radiation is a well-established process, little is known about the relationship between structure and property and the biological behavior of biomaterials obtained by thermal phenomena at 1070 nm wavelength. This study includes results concerning the use of a novel infrared radiation source (ytterbium laser fiber) for the synthesis of poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogel in order to produce medical devices. The materials were obtained by means of free radical polymerization mechanism and evaluated regarding its cross-linking degree, polymer chain mobility, thermal, and mechanical properties. Their potential use as a biomaterial toward cartilage tissue was investigated through incubation with chondrocytes cells culture by dimethylmethylene blue (DMMB) dye and DNA quantification. Differential scanning calorimetry (DSC) results showed that glass transition temperature (Tg) was in the range 103°C–119°C, the maximum degree of swelling was 70.8%, and indentation fluency test presented a strain of 56%–85%. A significant increase of glycosaminoglycans (GAGs) concentration and DNA content in cells cultured with 40 wt% 2-hydroxyethyl methacrylate was observed. Our results showed the suitability of infrared laser fiber in the free radicals formation and in the rapid polymer chain growth, and further cross-linking. The porous material obtained showed improvements concerning cartilage tissue regeneration.

Description: Araçá fruit extracts were dried at different air conditions, and an investigation of the impact of drying on the volatile composition and antioxidant activity of araçá extracts was conducted. The effective moisture diffusivity varied between 8.542 × 10−8 and 13.34 × 10−8 m2/min. Fruit extracts dried at 50°C and 2.0 m/s had the highest total antioxidant activity (1916.10 mgascorbic acid/100 garaçá). The highest phenolic content (556.28 mgGAE/100 garaçá) was obtained when fruits were dried at 40°C and 1.5 m/s, but the resulting extract contained high amounts of 5-hydroxymethylfurfural (HMF), a contaminant formed in sugar-rich foods as a result of heating. Araçá extracts had similar qualitative profiles of volatile compounds by GC-MS, with caryophyllene being the most abundant terpene, followed by 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, selina-3,7(11)-diene, γ-terpinene, γ-cadinene, and α-salinene. HMF corresponded to the major peak in all chromatograms, proving that thermal drying affected the quality of the extracts.

Description: Plate heat exchangers (PHEs) play an important role in different technical fields, namely, in energetics, chemical industry, food industry, and others. To use PHE effectively, it is necessary to have correct data for pressure drop. Unfortunately, in open literature, a large difference among different authors occurs. In this work is shown that an essential portion of this difference lies in the choice of the typical length for the calculation of the friction coefficient. Care must be taken to consider the pressure drop of the distribution zone. A three-component model for hydraulic resistance of PHE in turbulent flow regime is proposed in this work. The proposed model shows good agreement with experimental data.

Description: The present study aims to investigate the catalytic ethanol dehydration to higher value products including ethylene, diethyl ether (DEE), and acetaldehyde. The catalysts used for this reaction were WO3/TiO2 catalysts having W loading of 13.5 wt.%. For a comparative study, the TiO2 supports employed were varied by two different preparation methods including the sol-gel and solvothermal-derived TiO2 supports, denoted as TiO2-SG and TiO2-SV, respectively. It is obvious that the different preparation methods essentially altered the physicochemical properties of TiO2 supports. It was found that the TiO2-SV exhibited higher surface area and pore volume and larger amounts of acid sites than those of TiO2-SG. As a consequence, different characteristics of support apparently affected the catalytic properties of WO3/TiO2 catalysts. As expected, both catalysts WO3/TiO2-SG and WO3/TiO2-SV exhibited increased ethanol conversion with increasing temperatures from 200 to 400°C. It appeared that the highest ethanol conversion (ca. 88%) at 400°C was achieved by the WO3/TiO2-SV catalysts due to its high acidity. It is worth noting that the presence of WO3 onto TiO2-SV yielded a remarkable increase in DEE selectivity (ca. 68%) at 250°C. In summary, WO3/TiO2-SV catalyst is promising to convert ethanol into ethylene and DEE, having the highest ethylene yield of ca. 77% at 400°C and highest DEE yield of ca. 26% at 250°C. These can be attributed to proper pore structure, acidity, and distribution of WO3.

Description: Nitrobenzene is widely produced via benzene nitration to be applied in several industries such as pharmaceutical, textile, and agricultural. In this work, an exergy sensibility analysis was performed with the aim of identifying possible opportunities of process improvements. The irreversibilities, exergy of wastes, and efficiency were calculated per stage through exergy balance. The simulation software Aspen plus V10.1 provided the physical exergies of process streams while chemical exergies were found in literature. A sensibility analysis was also carried out in order to study the effect of efficiency of some stages (polyfunctional reaction and cooling 1) on global exergy efficiency. This analysis reveals that nitrobenzene production from benzene is an efficient process from an exergy viewpoint (88%). The total irreversibilities, total exergy of wastes, and exergy of utilities-inlet were calculated in 41,647,341.85 MJ/h, 5,537,487.3 MJ/h, and 18,137,363.71 MJ/h, respectively. The results obtained from sensibility analysis suggested that heat flow of heat exchangers HE-201, HE-303, and HE-301 could provide energy requirements for heating.

Description: A coupled numerical code of the Euler-Euler model and the population balance model (PBM) of the liquid-liquid dispersions in a spray fluidized bed extractor (SFBE) has been performed to investigate the hydrodynamic behavior. A classes method (CM) and two representatively numerical moment-based methods, namely, a quadrature method of moments (QMOM) and a direct quadrature method of moments (DQMOM), are used to solve the PBE for evaluating the effect of the numerical method. The purpose of this article is to compare the results achieved by three methods for solving population balance during liquid-liquid two-phase mixing in a SFBE. The predicted results reveal that the CM has the advantage of computing the droplet size distribution (DSD) directly, but it is computationally expensive if a large number of intervals are needed. The MOMs (QMOM and DQMOM) are preferable to coupling the PBE solution with CFD codes for liquid-liquid dispersions simulations due to their easy application, reasonable accuracy, and high reliability. Comparative results demonstrated the suitability of the DQMOM for modeling the spray fluidized bed extractor with simultaneous droplet breakage and aggregation. This work increases the understanding of the chemical engineering characteristics of multiphase systems and provides a theoretical basis for the quantitative design, scale-up, and optimization of multiphase devices.

Description: Application of carbon nanomaterials in oil well drilling fluid has been previously studied and was found to enhance its filtration properties. There is a general consensus that addition of colloids in suspension will alter its rheology, i.e., carbon nanomaterials, in this research work; graphene nanoplatelets are hydrophobic materials, which require functionalisation to improve its dispersion in aqueous solution. However, different degrees of dispersion may vary the rheological properties behaviour of drilling fluid. The objective of this study was to characterize the colloidal dispersion of graphene nanoplatelets (GNP) in aqueous solution and its impact on the rheological properties behaviour of water-based drilling fluid. Dispersion of graphene nanoplatelets was achieved through noncovalent functionalisation by means of surfactant attachment. UV-visible spectroscopy was employed to analyze the dispersion of GNP in aqueous solution. The rheological test was carried out using a simple direct-indicating viscometer at six different speeds. Results revealed that the degree of dispersion of GNP using Triton X-100 was generally higher than both SDS and DTAB. Comparison between the rheological properties behaviour of drilling fluid with GNP dispersed using different surfactants shows little to no difference at low shear rates. At high shear rates, however, greater dispersion of GNP shows higher thinning properties while fluid with a low dispersion of GNP exhibited linear behaviour to thickening properties.

Description: Direct conversion of fructose into 5-hydroxymethylfurfural (HMF) is achieved by using modified aluminum-molybdenum mixed oxide (S-AlMo) as solid acid catalysts. The synthesized catalyst was characterized by powder XRD, nitrogen adsorption-desorption isotherm, NH3-TPD, and SEM. As a result, the presence of strong acidity, mesostructures, and high surface area in the S-AlMo catalyst was confirmed by nitrogen adsorption-desorption isotherm and NH3-TPD studies. A study by optimizing the reaction conditions such as catalyst dosage, reaction temperature, and time has been performed. Under the optimal reaction conditions, HMF was obtained in a high yield of 49.8% by the dehydration of fructose. Moreover, the generality of the catalyst is also demonstrated by glucose and sucrose with moderate yields to HMF (24.9% from glucose; 27.6% from sucrose) again under mild conditions. After the reaction, the S-AlMo catalyst can be easily recovered and reused four times without significant loss of its catalytic activity.

Description: The modelling and numerical simulation of the drying process in porous media are discussed in this work with the objective of presenting the drying problem as the system of governing equations, which is ready to be solved by many of the now widely available control-volume-based numerical tools. By reviewing the connection between the transport equations at the pore level and their up-scaled ones at the continuum level and then by transforming these equations into a format that can be solved by the control volume method, we would like to present an easy-to-use framework for studying the drying process in porous media. In order to take into account the microstructure of porous media in the format of pore-size distribution, the concept of bundle of capillaries is used to derive the needed transport parameters. Some numerical examples are presented to demonstrate the use of the presented formulas.

Description: In this paper, the Kedem–Katchalsky equations in matrix form for nonhomogeneous ternary nonelectrolyte solutions were applied for interpretation of transport through the membrane mounted in horizontal plane. Coefficients ,, and (for nonhomogeneous solutions), Hij and (for homogeneous solutions) (i, j ∈ {1, 2, 3}, r = A, B), , and were calculated on the basis of experimentally determined coefficients (Lp, σ1, σ2ω11, ω22, ω21, ω12, , and ) for glucose in aqueous ethanol solutions and two configurations of the membrane system. From the calculations, it results that the values of coefficients ,,,,,, and depend nonlinearly on solution concentration as well as on a configuration of membrane system. Besides, the values of coefficients ,,,,, and depend linearly on solution concentration. The value of coefficients H13, H23, and H33 do not depend on solution concentration. The coefficients ψ12, ψ13, ψ22 = ψ23, ψ32 = ψ33, and ψdet depend nonlinearly on solution concentration and for  ≈ 9.24 mol m−3 are equal to zero. For   9.23 mol m−3, positive. In contrast, the values of coefficients ψ22 = ψ23, ψ32 = ψ33, and ψdet for   9.24 mol m−3, negative. For  = 0, we can observe nonconvective state, in which concentration Rayleigh number reaches the critical value RC = 1691.09, for is convective state with convection directed straight down and for is convective state with convection directed straight up.

Description: Focusing on the insufficient estimation of the local pressure loss at a 90° horizontal-vertical bend in low-pressure pneumatic conveying of coarse particles, experiments are conducted in a 80 mm inner diameter test bend by using polyethylene particles having an equivalent spherical diameter of 4.00 mm. The influences of the local pressure loss versus the gas flow Reynolds number, the solid-gas ratio, and the bending radius ratio are investigated. Based on the additional pressure theory of Barth, an empirical formula estimating the local pressure loss is obtained using dimensional and nonlinear regression analysis. Summarizing the experiments and literature, the results expound on the local gas flow pressure loss coefficient decreases with increasing Reynolds number, and first decreases and then increases with increasing bending radius ratios from 0.5 to 7. The additional solid flow pressure loss coefficient decreases with the increasing Reynolds number and bending radius ratio in the dilute phase, and linearly increases with increasing solid-gas ratio. Compared with the estimated values with the experimental values, the calculated standard deviation is below 4.11%, indicating that the empirical formula can be used to predict local pressure loss at the bend in the low-pressure dilute-phase pneumatic conveying.

Description: In the present study, the experimental design method was used to optimize the preparation conditions of an activated carbon from prickly pear seed cake by phosphoric acid activation. The parameters studied include impregnation ratio, carbonization temperature, and carbonization time. The optimal conditions for the preparation of the activated carbon with high adsorption capacity for methylene blue were identified to be an impregnation ratio of 2.9, carbonization temperature of 541°C, and carbonization time of 88 min. The obtained activated carbon was characterized by SEM/EDX, FTIR, pHpzc, and its capacity to adsorb methylene blue. FTIR analysis and pHPZC showed the acidic character of the activated carbon surface. The adsorption capacity of the optimal activated carbon was found to be 260 mg·g−1 for methylene blue. The adsorption equilibrium of methylene blue was well explained by the pseudo-second-order model and Freundlich isotherm. Furthermore, the performance of the produced activated carbon was examined by the methyl orange removal.

Description: Oil palm trunk is a kind of biomass rich in starch content. Oil palm trunk waste was available throughout the year in Malaysia and Indonesia due to continuous felling of nonproductive, over 25-year-old trees. Even though some manufacturers were using it in plywood and veneer production, they are hard to handle which later becomes less favorable raw materials due to a high moisture content where combination with a high starch content quickly attracts fungus and wood-decaying agents. The objective of this work was to evaluate properties of experimental wood composite panels, manufactured using oil palm-extracted starch modified with glutardialdehyde (OPSMG) as a binder. Different analyses were employed to characterize the properties of the samples besides evaluation of bending, internal bonding strength, and dimensional stability of the panels. Characterization on the functional group using the FT-IR analysis showed presence of aldehyde groups and ketone stretching vibrations at 1736.05 cm−1 and 1596.25 cm−1, which proves the presence of glutardialdehyde besides formation of bonding between the OPSMG and the woody materials. The XRD analysis showed the starch modification had lowered the crystallinity index which in turn increased the strength of the manufactured wood composites. The OPSMG wood composites were also found to have lower thermal stability, as evaluated using the TGA analysis. It was recorded that the maximum modulus of rupture for OPSMG wood composites was achieved at the 0.80 g/cm3 density level with an average value of 15.446 N/mm2 which showed 38.00% increment in strength between those two types of wood composites. Thickness swelling after immersion in water can still be improved by incorporating the moisture-repellent material later. After analyzing the results, it was concluded that modified oil palm starch has the potential to be used as an environment friendly binder for wood composite making.

Description: In this work, glass-ceramics were produced with mechanical and physical properties, using recycled glass powder from windshields as raw material. The glass powder was formed and sintered at temperatures 600, 650, 700, 750, and 800°C. Pieces were also produced with the addition of niobium oxide to the glass powder. The flexural strength and the Archimedes density of the produced parts were determined. The reliability of the results was evaluated by the Weibull statistic. X-ray diffraction was performed. Maximum flexural strength was 77.64 MPa at 750°C, with the addition of niobium oxide at 43.86 MPa at 700°C. X-ray diffraction showed crystalline structures in the specimens with the addition of the nucleating agent, confirming the production of glass-ceramics in this composition. The pure glass powder only crystallized from 750°C. The Nb2O5 favors the formation of crystalline structures in the vitreous matrix at low temperatures and with piezoelectric structures.

Description: In this study, corn cobs (CC) and Cedrela odorata (CO) sawdust which are common waste materials in Nigeria were used as raw materials in the production of bio-oil through pyrolysis at 500°C, for 2 h. The biochar produced in the process was sulfonated with concentrated sulfuric acid under reflux at 150°C for 6 h and used as a solid acid catalyst for bio-oil upgrading. The bio-oil was upgraded by simultaneous olefination and esterification using 3,7-dimethyloct-1-ene and butanol which served as a reagent and cosolvent. FT-IR spectra of the activated biochar from CC and CO raw materials showed an absorbance in the range of 1032–1180 cm−1, which is indicative of asymmetric S=O bonds, and the spectra also revealed a band between 3400 and 3700 cm−1, which indicated presence of hydrogen-bonded hydroxyl groups and thus successful activation of the biochar. This observed IR absorbance was absent in the nonactivated biochar. Proximate analysis of upgraded bio-oils revealed a significant reduction in percentage water and oxygen contents, an increase in the high heating value (HHV) and flammability. The chemical composition of the bio-oils was determined using GC-MS, and it showed significant reduction in oxygenated compounds in the upgraded bio-oil as against their high composition in raw bio-oils.

Description: Crude glycerol (CG) can be used as a substrate for microbial bioconversion. However, due to presence of many impurities, many microorganisms are unable to utilise this substrate efficiently. The present study is trying to improve CG using as the feedstock of Aspergillus terreus for the production of lovastatin, (+)-geodin, and sulochrin. The CG was pretreated chemically (solvents) and physically (activated carbon (AC) and water softener (WS)) to separate most of the impurities from the CG. For solvent pretreatments, petroleum ether (PE) produced the largest increase of lovastatin (92.8%) when compared to positive control and pure glycerol (PG) and up to 820% when compared to negative control (CG). In contrast, diethyl ether (DE) produced the largest increase in (+)-geodin at 80.81% (versus CG) and 176.23% (versus PG). The largest increase in toluene (Tol) was observed in sulochrin production, at 67.22% (versus CG) and 183.85% (versus PG). For physical pretreatments, the pattern of metabolite production in AC (lovastatin: 20.65 mg/L, (+)-geodin: 7.42 mg/L, sulochrin: 11.74 mg/L) resembled PG (lovastatin: 21.8 mg/L, (+)-geodin: 8.60 mg/L, sulochrin: 8.18 mg/L), while WS (lovastatin: 11.25 mg/L, (+)-geodin: 15.38 mg/L, sulochrin: 16.85 mg/L) resembled CG (lovastatin: 7.1 mg/L, (+)-geodin: 17.10 mg/L, sulochrin: 14.78 mg/L) at day 6 of fermentation. These results indicate that solvent pretreatments on CG are excellent for metabolites production in A. terreus, depending on the solvents used. In contrast, physical pretreatments are only feasible for (+)-geodin and sulochrin production. Therefore, different strategies can be employed to manipulate the A. terreus bioconversion using improved CG by using a few simple pretreatment strategies.

Description: The higher cost of chemical surfactants has been one of the main reasons for their limited used in enhanced oil recovery (EOR) process. Hence, the reason for developing lignin-based surfactant is to lower the cost of chemicals as it does not tie to the price of crude oil as compared to petroleum-based surfactants. Besides, lignin is biodegradable and easily extracted from plant waste. The objectives of this study are to determine the formulations of the lignin-based surfactant for EOR applications and to determine the oil recovery performance of the formulated surfactants through surfactant flooding. The lignin-based surfactants were formulated by mixing the lignin with the amine (polyacrylamide or hexamethylenetetramine) and the surfactant sodium dodecylbenzenesulfonate in a 20,000 ppm NaCl brine. Interfacial tension (IFT) of the formulated lignin-based surfactant is measured at ambient temperature using the spinning drop method. The displacement experiments were conducted at room temperature in glass beads pack holders filled with glass beads, saturated with paraffin and brine. The results of the study showed that the best formulation of lignin-based surfactant is using hexamethylenetetramine as the amine, lignin, and sodium dodecylbenzenesulfonate at 2% total active concentration. The oil recovery and interfacial tension using the lignin amine system is comparable with the commercial petroleum sulfonate system.

Description: Hydrocarbons are the most important source for hydrogen production. A combined reaction-separation process using inorganic membranes can significantly increase the reaction conversion by shifting the equilibrium toward product formation. Sulfur poisoning is a significant problem as it deactivates the most commonly used metallic membranes. The relationship of the membrane activity and surface coverage with the surface structure has been recognized in the literature. A theoretical model to simulate hydrogen transport in the presence of sulfur compounds is presented. This model accounts for active site deactivation and permanent structural damage to the membrane. Transport and reaction rate parameters used in the model have been estimated from experimental data. Qualitatively, the model represents well the behavior of inorganic membranes, including partial membrane activity regeneration after the sulfur source is removed.

Description: Introduction. Adsorption is a purification process with a more efficient energy level than others. Adsorption performance is strongly influenced by the ability of the adsorbent to be used; therefore, the modification of the adsorbent becomes a very important key for the purification process that occurs. Methods. In this study, the preparation of composite adsorbents was carried out by combining polyvinyl alcohol (PVA), zeolite (Zeo), and activated carbon (AC) as precursors. The crosslinking process was fulfilled by adding glutaraldehyde to the precursor mixtures followed by a supercritical fluid CO2 extraction (SFE) technique to create conditions for the crosslinking process. The composites were analyzed using Braunner–Emmet–Teller (BET) surface area analysis, Fourier-transform infrared (FTIR), differential scanning calorimetry (DSC), and scanning electron microscopy with energy dispersive X-ray (SEM/EDX-mapping), while individual and composite adsorbents were evaluated for their ability in bioethanol dehydration at various initial concentrations of ethanol and temperature. Results. The BET characterization shows that composite preparation under supercritical CO2 conditions provides reasonable surface areas, which are proportional to the content of activated carbon. The crosslinking process has been described by FTIR data interpretation, showing that PVA and glutaraldehyde were properly distributed on Zeo and AC precursors. The DSC characterization results give information that PVA successfully forms hydrophilic composites within Zeo and AC. The SEM micrograph analysis shows the formation of pores on the surface and cross section in structured adsorbents. The experimental adsorption shows that an increasing amount of AC in the composites increases the capacity of water adsorption (i.e., 0.80 gram of water/gram of adsorbent for PVA/Zeo/AC = 1 : 1 : 1 at 22°C). However, the effect is not significant when the ratio of AC is less than 0.5. As expected, the lower temperature increases the adsorption capacity. Further, by using approximately 4.5 gram adsorbents composite in 30 ml of water-ethanol mixtures, high concentration of bioethanol (〉99%) can be achieved at various temperatures from 22°C to 40°C and bioethanol initial concentration from 88% to 96%. Conclusion. The SFE technique provides distinguished adsorbents composite properties. Further, the new composites provide about four times better adsorption capacity than that showed in the individual adsorbents test. The addition of AC influences on increasing the capacity and adsorption kinetics value.

Description: This paper focuses on understanding the electrolyte flow characteristics in a typical packed-bed electrochemical reactor using Residence Time Distribution (RTD) studies. RTD behavior was critically analyzed using tracer studies at various flow rates, initially under nonelectrolyzing conditions. Validation of these results using available theoretical models was carried out. Significant disparity in RTD curves under electrolyzing conditions was examined and details are recorded. Finally, a suitable mathematical model (Modified Dispersed Plug Flow Model (MDPFM)) was developed for validating these results under electrolyzing conditions.

Description: This paper was focused on the method to increase of the sorption properties in the flax fibrous material. This method was based on the original approach which includes the application of enzymatic catalysis as a destruction regulator of the polycarbohydrate components in the bast. The formed reaction products were used as reagents for reductive destruction of lignin. The changes in the fiber sorption capacity to the molecular markers were controlled after changing both the polymer composition of the fiber and the size of its pore. It was determined that the flax sorbents increase the adsorption of phenol vapors to 9–12 times and organic dyes from aqueous solutions to 4 times.

Description: EPX-2R is a high-performance plastic explosive produced for different applications. EPX-2R is based on RDX (1,3,5-trinitro-1,3,5-triazinane) bonded by the elastic matrix of the softened styrene butadiene binder. A computerizing mixer plastograph was used for the production of EPX-2R. The internal energy of combustion was measured and used to determine the enthalpy of formation. Friction and impact sensitivities were measured. The velocity of detonation was determined experimentally, and the detonation properties were calculated by the EXPLO 5 code. For comparison, traditional plastic explosives, composition C-4, Semtex 10, Formex P1, EPX-1, and Sprängdeg m/46, were studied. It was concluded that the velocity of detonation of EPX-2R was higher than the studied samples except composition C-4, while its sensitivity is the lowest. Interesting inversely proportional relationship between the measured internal energy of combustion and the calculated heat of detonation was observed.

Description: In this study, vapour-liquid equilibrium of CO2-loaded aqueous potassium salt of L-histidine was studied for a wide range of temperature (313.15–353.15 K), pressure (150–4000 kPa), and solvent concentrations (1–2.5 molar). The experimental results show that L-histidine has an excellent absorptive capacity for carbon dioxide. When compared to conventional solvent (monoethanolamine) and amino acid salt (potassium L-lysinate) at similar process conditions, L-histidine has superior absorption capacity. Moreover, modified Kent–Eisenberg model was used to correlate the VLE of the studied system with excellent agreement between the model and experimental values. The model exhibited an AARE% of 7.87%, which shows that it can satisfactorily predict carbon dioxide solubilities in aqueous potassium salt of L-histidine at other process conditions. Being a biological component in origin, almost negligibly volatile, and highly resistant to oxidative degradation, L-histidine offers certain operational advantages over other solvents used and has a promising potential for carbon dioxide capture.

Description: This paper reports the investigation of zeolite NaY synthesized from kaolin, a locally abundant soil material found in the Benin City metropolis, Nigeria, as a suitable catalyst and its effect on the properties of pyrolytic oil produced from used tires. The pyrolysis process was conducted from a range of 1 to 10 wt.% of catalyst concentration to the used tire at an operating temperature of 600°C, heating rate of 15°C/min, and particle size of 6 mm. An increase in the catalyst weight gave a maximum yield of catalytic pyrolytic oil (CPO) of 21.3 wt.% at a catalyst-to-tire ratio of 7.5 wt.%. Although this was lower than the noncatalyzed pyrolytic oil yield (34.40 wt.%), the quality in terms of chemical composition and hydrocarbon fuel range varied from that of the noncatalyzed pyrolytic oil, as indicated by the FT-IR, NMR, and GC-MS analyses. From the GC-MS result, the CPO gave a benzene yield higher than that of noncatalyzed pyrolytic oil. The CPO benzene yield can be ranked as CPO (5 wt.%) 〉 CPO (1 wt.%) 〉 CPO (10 wt.%) 〉 CPO (7.5 wt.%) 〉 noncatalyzed pyrolytic oil. The catalyst also improved the yield of other valuable chemicals such as ethylbenzene, o- and p-xylene, styrene, toluene, quinoline, pyrene, thiophene, P-cresol, phenol, and limonene in the pyrolytic oil. For hydrocarbon range, the catalyst displayed the potential to increase the yield of carbon range (C6–C15), which is similar to gasoline (C6–C12) and kerosene (C11–C14), with a lower yield of diesel and fuel oils (C11–C20) when compared to the noncatalyzed pyrolytic oil.

Description: In this study, iron nanoparticles (FeNPs) were synthesized via a green method using loquat (Eriobotrya japonica) leaves aqueous extract as a renewable reducing agent. The synthesized FeNPs were characterized by DLS, XRD, FT-IR, SEM/EDX, and TEM analysis, and then, they were used as an adsorbent for Cr(VI) removal from aqueous solutions. Batch adsorption experiments were carried out to investigate the optimum adsorption parameters such as the initial pH of the solution, temperature, initial Cr(VI) concentration, and adsorbent concentration. The optimum adsorption conditions were determined as initial pH 3.0, temperature 45°C, and adsorbent concentration 1 g/L. Also, a linear increase was observed in adsorbed Cr(VI) amounts with the increasing initial Cr(VI) concentrations. The biosynthesized FeNPs showed the high removal levels higher than 90% for Cr(VI) adsorption at a wide range of initial Cr(VI) concentrations (50–500 mg/L). The experimental equilibrium data were modelled with Langmuir and Freundlich isotherm models, and it was found that experimental equilibrium data could be well described by the Langmuir isotherm model. The maximum monolayer coverage capacity of FeNPs for Cr(VI) adsorption was found to be 312.5 mg/g. The pseudo-first-order and the pseudo-second-order kinetic models were applied to the experimental adsorption data, and it was concluded that the data were defined as the best agreement with the pseudo-second-order kinetic model. Weber–Morris model was used to investigate the effect of mass transfer on the adsorption of Cr(VI) onto FeNPs; it was observed that both the film (boundary layer) and intraparticle diffusion affected the studied adsorption process. The thermodynamic studies suggested that Cr(VI) adsorption onto FeNPs was endothermic and nonspontaneous, and the positive ΔS value indicated increased disorder at the solid-solution interface during the adsorption.

Description: Power consumption is an important parameter for the design of mixing equipment. The aim of this study is to develop a new correlation of the power consumption of a double impeller. The effect of impeller spacing on the double-impeller flow pattern and power consumption was investigated in the laminar region. As a result, the effect of impeller spacing on the flow pattern was described based on the ratio of impeller spacing to the impeller blade height. Moreover, the power consumption of a double impeller could be correlated with the same ratio.

Description: Traveling wave analysis of a recently developed two-fluid model for bubbly flow in lab-size packed beds is used to propose a constitutive closure for the effective viscosity, a nonzero parameter that is needed in the liquid momentum balance to avoid the prediction of disturbances with an infinite growth rate. Near-solitary wave profiles are predicted over a range of velocity parameters consistent with linear stability analysis. Centimeter-scale periodic disturbances are predicted in the near-pulsing regime. Preliminary estimates of average pulse properties compare well with typically reported experimental values. Initial comparison with time integration subject to periodic boundary conditions shows agreement of the liquid saturation profiles but differences in the liquid velocity profiles.

Description: In this research, the adsorption potential of quaternized palm kernel shell (QPKS) to remove F− from aqueous solution was investigated using fixed-bed adsorption column. Raw palm kernel shell waste was reacted with 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHMAC) in order to modify the surface charge. The effects of inlet F− concentrations (2–12 mg/l) and QPKS bed height (2–10 cm) with optimum pH (pH = 3) on the breakthrough characteristics of the adsorption system were determined. In the fixed-bed column, breakthrough time increases with increasing bed height due to increasing amount of active site on adsorbents to adsorb the fluoride ion. Decreasing trend of breakthrough values was obtained with increasing initial fluoride concentration due to greater driving force for the transfer process to overcome the mass transfer resistance in the column. The adsorptions were fitted to three well-established fixed-bed adsorption models, namely, Thomas, Yoon–Nelson, and Adams–Bohart models. The results fitted well to the Thomas and Yoon–Nelson models with correlation coefficient, R2 ≥ 0.96.

Description: Ionic liquid mixed matrix membranes (IL3Ms) were synthesized using polyethersulfone (PES) as the base polymer and silica-aluminophosphate (SAPO-34) as the dispersed particles, and their CO2 permeation was investigated. Three of the most widely used models for gas separation—the Maxwell, Lewis–Nielson, and Maxwell–Wagner–Sillar (MWS) models—were then applied to the membranes. Large deviations were found between the model predictions and experimental data. FESEM images suggested that local agglomeration and disorientation of the SAPO-34 particles within the membrane afforded substantial changes in the morphology. The MWS model, which considers the shape factor, was modified to incorporate the volume fraction of the wetted dispersed phase and the ideal shape factor. A direct relationship was found between the filler concentration and the shape factor. The modified model was shown to produce absolute and relative errors of less than 3%. When validated against data from the literature, the deviation remained within 5%. The modified model can be used to estimate the gas permeance of an IL3M.

Description: Ammonium phosphate fire-extinguishing agents are one of the best substitutes for halon in many powder media. Here, 11 μm median diameter ammonium phosphate ultrafine dry powder was used as a fire-extinguishing medium. The fire-extinguishing performance of ultrafine powder under different pressures was studied by analyzing fire-extinguishing time, amount of extinguishing agent, and temperature during the fire-extinguishing process. The results show that the fire-extinguishing performance of the ultrafine powder is improved with increasing injection pressure. Finally, we used FDS software for fire simulation to study the influence of injection pressure on the extinguishing agent. The results show that the extinguishing time is shortened with increasing injection pressure. From 0.2 MPa to 1.0 MPa, the extinguishing time decreases from 34 seconds to 4 seconds.

Description: Oil recovery was improved using the tertiary amine, N,N-dimethylcyclohexylamine (DMCHA), a powerful and promissory switchable solvent, in simulated conditions similar to the Colombian crude oil reserves. Firstly, the Colombian crude oil (CCO) and the soil were characterized completely. Afterwards, an aged crude-rock system was obtained to use DMCHA that gave an oil crude extraction of 80% in our preliminary studies. Thus, a sand-pack column (soil-kaolin, 95 : 5) frame saturated with CCO was used to simulate the conditions, in which DMCHA could recover the oil. After the secondary recovery process, 15.4–33.8% of original oil in place (OOIP) is obtained. Following the injection of DMCHA, the recovery yield rose to 87–97% of OOIP. Finally, 54–60% of DMCHA was recovered and reinjected without affecting its potential in the simulated conditions.

Description: A moving boundary model for food isothermal drying and shrinkage is applied to predict the time decay of water content and sample volume, as well as water diffusivity for chayote discoid slices in the temperature range 40–70°C. The core of the model is the shrinkage velocity , assumed equal to the water concentration gradient times a shrinkage function α representing the constitutive equation of the food material under investigation. The aim is to provide a case study to analyze and quantify differences and accuracies of two different approaches for determining the shrinkage function α from typical experimental data of moisture content vs. rescaled volume : a fully analytical approach and a shortcut numerical one.

Description: The effect of copper, zinc, chromium, and lead on the anaerobic co-digestion of waste activated sludge and septic tank sludge in Hanoi was studied in the fermentation tests by investigating the substrate degradation, biogas production, and process stability at the mesophilic fermentation. The tested heavy metals were in a range of concentrations between 19 and 80 ppm. After the anaerobic tests, the TS, VS, and COD removal efficiency was 4.12%, 9.01%, and 23.78% for the Cu(II) added sample. Similarly, the efficiencies of the Zn(II) sample were 1.71%, 13.87%, and 16.1% and Cr(VI) efficiencies were 15.28%, 6.6%, and 18.65%, while the TS, VS, and COD removal efficiency of the Pb(II) added sample was recorded at 16.1%, 17.66%, and 16.03% at the concentration of 80 ppm, respectively. Therefore, the biogas yield also decreased by 36.33%, 31.64%, 31.64%, and 30.60% for Cu(II), Zn(II), Cr(VI), and Pb(II) at the concentration of 80 ppm, compared to the raw sample, respectively. These results indicated that Cu(II) had more inhibiting effect on the anaerobic digestion of the sludge mixture than Zn(II), Cr(VI), and Pb(II). The relative toxicity of these heavy metals to the co-digestion process was as follows: Cu (the most toxic) 〉 Zn 〉 Cr 〉 Pb (the least toxic). The anaerobic co-digestion process was inhibited at high heavy metal concentration, which resulted in decreased removal of organic substances and produced biogas.

Description: The unprecedented rise in carbon dioxide levels due to anthropogenic activities, if left unchecked, can lead to increased global warming. Electricity and heat generation account for around 25% of this greenhouse gas emission. The Allam cycle, a new oxy-fuel power cycle that emits virtually no CO2 and NOx, is inherently integrated with an air separation plant. In this study, Aspen Plus Dynamics was used to model the integrated Allam power plant/air separation unit (ASU) with a high degree of heat and work integration. The steady-state model developed agrees with the model developed by Net Power. Regulatory and advanced PID controllers were implemented for major equipment to meet operation objectives. Controller set point change, power ramp down, and natural gas composition change were studied, and key plant performance indicators were monitored and analyzed. This study shows that the Allam cycle power plant integrated with an ASU is controllable with the proposed control strategy under a tightly integrated configuration.

Description: Water pollution by heavy metals like Co(II) is particularly of concern because of their persistence in the environment, toxicity, and ability to bioaccumulate in organisms. In this study, the influence of contact time at three initial concentration, pH, adsorbent dose, temperature, and kinetics, thermodynamics, and one-, two-, and three-parameter isotherm modeling of the adsorption of Co(II) on neem leaves (DNL) was investigated. The adsorbent was characterized using FTIR, TGA-DSC, EDX, and nitrogen adsorption-desorption. DNL is composed of many Co(II) surface-binding groups and a BET surface area of 0.2783 m2/g dominated by meso- and macropores. Equilibrium was attained in 10 minutes for the three concentrations with a removal efficiency of 85–97%. ∆G° of −5.424 to −6.068 KJ/mol at 25 to 60°C, respectively, indicated spontaneous adsorption with increasing temperature. D-R adsorption energies of 0.649 to 2.433 KJ/mol revealed physical adsorption. Maximum adsorption capacity of 9.201–523.900 mg/g was obtained by Freundlich and Jovanovic isotherms. Adsorption was very favourable as evident by the high Kiselev equilibrium constant (11.652–172.78 L/mg) and very low RL values of 0.001–0.026. Adsorption occurred by repulsive mechanism as indicated by Fowler–Guggenheim and Hill–de Boer negative interaction energies (−16.182 to −90.163 and −111.102 to −3328.86 KJmol−1, respectively), confirming maximum Co(II) adsorption at pH 3. Results can be used in the design of an efficient adsorption system using neem leaves which is very efficient in removing low and high levels of heavy metals like cobalt ions from wastewater.

Description: In line with the growing environmental awareness developed along the last decades, modern societies are urged to evolve into sustainable economics where the reuse of organic wastes represents the key feedstock for a green transaction. The oil phase obtained from different biomasses has the potential to be a source of food supplements, medicines, cosmetics, or feedstock for biofuel production. In the present work, the composition of 104 different biomasses including seeds, peels, flowers, plants, and leaves has been reviewed for the lipid content. Based on the most frequent fatty acids screened, experimental data for normal boiling point temperature, normal melting point, critical properties, and acentric factor were collected and compared with the most common estimation methods, which are functions of the molecular structure and interaction between different functional groups. New predictive equations have been proposed to reduce the estimation deviation and to provide simple correlations to be used in simulation software when dealing with biomass processes. For all the properties, the estimations proposed have an absolute average deviation equal to or lower than 4.6%.

Description: In this study, a nonisothermal kinetics analysis of petcoke was performed at heating rates of 10, 15, and 20°C/min using thermal gravimetric analysis (TGA). The behaviour of petcoke at different gasification stages (dewatering, volatilization, char burning, and burnout) was studied. The effect of heating rate on the activation energy of petcoke gasification was also investigated. The activation energy of petcoke was estimated using different kinetic models that include volume reaction model (VRM), shrinking core model (SCM), random pore model (RPM), Coats and Redfern model (CRM), and normal distribution function (NDF). The NDF model was modified in this study. It was found that the experimental data were best fitted with the modified normal distribution function (MNDF) and SCM. The results also showed that activation energy decreases as heating rate increases, leading to reduction in gasification completion time.

Description: The sensitivity analysis of molybdenum disulfide nanoparticles synthesis process is studied using Aspen Plus with the aim of investigating the effect of reactants’ amounts on the production of molybdenum disulfide nanoparticles. The adopted approach consists in simulating the synthesis process based on experimental data, obtained at laboratory scale followed by sensitivity analysis with respect to the following precursors: ammonium heptamolybdate, elemental sulfur, and hydrazine used as a reducing agent. The sensitivity analysis revealed that the precursors have more significant impact on the obtained amount of molybdenum disulfide compared to hydrazine. The obtained result showed that the approach adopted in the study might be of interest for further investigation of the process design and scaling-up.

Description: Power consumption is an important parameter for the design of mixing equipment. The aim of this study is to develop a new correlation of the power consumption of a double impeller. The effect of impeller spacing on the double-impeller flow pattern and power consumption was investigated in the laminar region. As a result, the effect of impeller spacing on the flow pattern was described based on the ratio of impeller spacing to the impeller blade height. Moreover, the power consumption of a double impeller could be correlated with the same ratio.

Description: The effect of copper, zinc, chromium, and lead on the anaerobic co-digestion of waste activated sludge and septic tank sludge in Hanoi was studied in the fermentation tests by investigating the substrate degradation, biogas production, and process stability at the mesophilic fermentation. The tested heavy metals were in a range of concentrations between 19 and 80 ppm. After the anaerobic tests, the TS, VS, and COD removal efficiency was 4.12%, 9.01%, and 23.78% for the Cu(II) added sample. Similarly, the efficiencies of the Zn(II) sample were 1.71%, 13.87%, and 16.1% and Cr(VI) efficiencies were 15.28%, 6.6%, and 18.65%, while the TS, VS, and COD removal efficiency of the Pb(II) added sample was recorded at 16.1%, 17.66%, and 16.03% at the concentration of 80 ppm, respectively. Therefore, the biogas yield also decreased by 36.33%, 31.64%, 31.64%, and 30.60% for Cu(II), Zn(II), Cr(VI), and Pb(II) at the concentration of 80 ppm, compared to the raw sample, respectively. These results indicated that Cu(II) had more inhibiting effect on the anaerobic digestion of the sludge mixture than Zn(II), Cr(VI), and Pb(II). The relative toxicity of these heavy metals to the co-digestion process was as follows: Cu (the most toxic) 〉 Zn 〉 Cr 〉 Pb (the least toxic). The anaerobic co-digestion process was inhibited at high heavy metal concentration, which resulted in decreased removal of organic substances and produced biogas.

Description: A three-dimensional computational fluid dynamics (CFD) study was carried out for drilling fluid flow with drill cuttings in open channels. The flow is similar to the return flow when drilling, stream containing drilling fluid, and drill cuttings. The computational model is under the framework of the Eulerian multifluid volume of the fluid model. The Herschel–Bulkley rheological model was used to describe the non-Newtonian rheology of the drilling fluid, and the computational model was validated with experimental results for two-phase flow in the literature. The effect of flow depth and flow velocity in an open channel was studied for drill cutting size of up to 5 mm and for a solid volume fraction of up to 10%. For constant cross section and short open channels, the effect of drill cuttings on flow depth and mean velocity was found to be small for particle sizes less than 5 mm and solid volume fractions less than 10%. High momentum force in the downward direction can carry the solid-liquid mixture at higher velocities than a lower density mixture. Higher inclination angles mean that the gravity effect upon the flow direction is more significant than the particle friction for short channels.

Description: In this study, vapour-liquid equilibrium of CO2-loaded aqueous potassium salt of L-histidine was studied for a wide range of temperature (313.15–353.15 K), pressure (150–4000 kPa), and solvent concentrations (1–2.5 molar). The experimental results show that L-histidine has an excellent absorptive capacity for carbon dioxide. When compared to conventional solvent (monoethanolamine) and amino acid salt (potassium L-lysinate) at similar process conditions, L-histidine has superior absorption capacity. Moreover, modified Kent–Eisenberg model was used to correlate the VLE of the studied system with excellent agreement between the model and experimental values. The model exhibited an AARE% of 7.87%, which shows that it can satisfactorily predict carbon dioxide solubilities in aqueous potassium salt of L-histidine at other process conditions. Being a biological component in origin, almost negligibly volatile, and highly resistant to oxidative degradation, L-histidine offers certain operational advantages over other solvents used and has a promising potential for carbon dioxide capture.

Description: This study provided a basis for new possibilities concerning the use of the sugarcane bagasse ash as a green pozzolanic addition to the Portland cement composite. To that effect, a simple micronization method using air jet milling without any other additional thermal procedure was used to control the characteristics of ash particles. This procedure not only maintains the required characteristics of the residues but can also improve some of them. Sugarcane bagasse ash is a residue produced on large scale in Brazil by ethanol and sugar plants as a result of the burning of sugarcane bagasse in energy cogeneration. The residue used in this study was initially characterized by scanning electron microscopy, granulometric and specific mass analyses, N2 adsorption measurements, X-ray diffraction, X-ray fluorescence spectroscopy, and thermogravimetric analysis with differential thermal analysis. Pozzolanic ash activity was evaluated according to the axial compressive strength at 28 days and the modified Chapelle methods. The results showed that the milling fly sugarcane bagasse ash samples presented satisfactory pozzolanic activity.

Description: In this study, iron nanoparticles (FeNPs) were synthesized via a green method using loquat (Eriobotrya japonica) leaves aqueous extract as a renewable reducing agent. The synthesized FeNPs were characterized by DLS, XRD, FT-IR, SEM/EDX, and TEM analysis, and then, they were used as an adsorbent for Cr(VI) removal from aqueous solutions. Batch adsorption experiments were carried out to investigate the optimum adsorption parameters such as the initial pH of the solution, temperature, initial Cr(VI) concentration, and adsorbent concentration. The optimum adsorption conditions were determined as initial pH 3.0, temperature 45°C, and adsorbent concentration 1 g/L. Also, a linear increase was observed in adsorbed Cr(VI) amounts with the increasing initial Cr(VI) concentrations. The biosynthesized FeNPs showed the high removal levels higher than 90% for Cr(VI) adsorption at a wide range of initial Cr(VI) concentrations (50–500 mg/L). The experimental equilibrium data were modelled with Langmuir and Freundlich isotherm models, and it was found that experimental equilibrium data could be well described by the Langmuir isotherm model. The maximum monolayer coverage capacity of FeNPs for Cr(VI) adsorption was found to be 312.5 mg/g. The pseudo-first-order and the pseudo-second-order kinetic models were applied to the experimental adsorption data, and it was concluded that the data were defined as the best agreement with the pseudo-second-order kinetic model. Weber–Morris model was used to investigate the effect of mass transfer on the adsorption of Cr(VI) onto FeNPs; it was observed that both the film (boundary layer) and intraparticle diffusion affected the studied adsorption process. The thermodynamic studies suggested that Cr(VI) adsorption onto FeNPs was endothermic and nonspontaneous, and the positive ΔS value indicated increased disorder at the solid-solution interface during the adsorption.

Description: Ionic liquid mixed matrix membranes (IL3Ms) were synthesized using polyethersulfone (PES) as the base polymer and silica-aluminophosphate (SAPO-34) as the dispersed particles, and their CO2 permeation was investigated. Three of the most widely used models for gas separation—the Maxwell, Lewis–Nielson, and Maxwell–Wagner–Sillar (MWS) models—were then applied to the membranes. Large deviations were found between the model predictions and experimental data. FESEM images suggested that local agglomeration and disorientation of the SAPO-34 particles within the membrane afforded substantial changes in the morphology. The MWS model, which considers the shape factor, was modified to incorporate the volume fraction of the wetted dispersed phase and the ideal shape factor. A direct relationship was found between the filler concentration and the shape factor. The modified model was shown to produce absolute and relative errors of less than 3%. When validated against data from the literature, the deviation remained within 5%. The modified model can be used to estimate the gas permeance of an IL3M.

Description: A moving boundary model for food isothermal drying and shrinkage is applied to predict the time decay of water content and sample volume, as well as water diffusivity for chayote discoid slices in the temperature range 40–70°C. The core of the model is the shrinkage velocity , assumed equal to the water concentration gradient times a shrinkage function α representing the constitutive equation of the food material under investigation. The aim is to provide a case study to analyze and quantify differences and accuracies of two different approaches for determining the shrinkage function α from typical experimental data of moisture content vs. rescaled volume : a fully analytical approach and a shortcut numerical one.

Description: This paper reports the investigation of zeolite NaY synthesized from kaolin, a locally abundant soil material found in the Benin City metropolis, Nigeria, as a suitable catalyst and its effect on the properties of pyrolytic oil produced from used tires. The pyrolysis process was conducted from a range of 1 to 10 wt.% of catalyst concentration to the used tire at an operating temperature of 600°C, heating rate of 15°C/min, and particle size of 6 mm. An increase in the catalyst weight gave a maximum yield of catalytic pyrolytic oil (CPO) of 21.3 wt.% at a catalyst-to-tire ratio of 7.5 wt.%. Although this was lower than the noncatalyzed pyrolytic oil yield (34.40 wt.%), the quality in terms of chemical composition and hydrocarbon fuel range varied from that of the noncatalyzed pyrolytic oil, as indicated by the FT-IR, NMR, and GC-MS analyses. From the GC-MS result, the CPO gave a benzene yield higher than that of noncatalyzed pyrolytic oil. The CPO benzene yield can be ranked as CPO (5 wt.%) 〉 CPO (1 wt.%) 〉 CPO (10 wt.%) 〉 CPO (7.5 wt.%) 〉 noncatalyzed pyrolytic oil. The catalyst also improved the yield of other valuable chemicals such as ethylbenzene, o- and p-xylene, styrene, toluene, quinoline, pyrene, thiophene, P-cresol, phenol, and limonene in the pyrolytic oil. For hydrocarbon range, the catalyst displayed the potential to increase the yield of carbon range (C6–C15), which is similar to gasoline (C6–C12) and kerosene (C11–C14), with a lower yield of diesel and fuel oils (C11–C20) when compared to the noncatalyzed pyrolytic oil.

Description: Direct conversion of fructose into 5-hydroxymethylfurfural (HMF) is achieved by using modified aluminum-molybdenum mixed oxide (S-AlMo) as solid acid catalysts. The synthesized catalyst was characterized by powder XRD, nitrogen adsorption-desorption isotherm, NH3-TPD, and SEM. As a result, the presence of strong acidity, mesostructures, and high surface area in the S-AlMo catalyst was confirmed by nitrogen adsorption-desorption isotherm and NH3-TPD studies. A study by optimizing the reaction conditions such as catalyst dosage, reaction temperature, and time has been performed. Under the optimal reaction conditions, HMF was obtained in a high yield of 49.8% by the dehydration of fructose. Moreover, the generality of the catalyst is also demonstrated by glucose and sucrose with moderate yields to HMF (24.9% from glucose; 27.6% from sucrose) again under mild conditions. After the reaction, the S-AlMo catalyst can be easily recovered and reused four times without significant loss of its catalytic activity.

Description: Fruit consumption and processing result in considerable volumes of residual biomass. Transformation of this biomass into biosorbents offers an alternative for its reuse and disposal. As the green coconut shell is a waste often discarded in landfills and dumps, generating gases and leachate, two biosorbents were developed from the epicarp and mesocarp of green coconut to adsorb fluoride ions in aqueous solution. The kinetic experiments showed that sorption of fluoride ions reached equilibrium at 300 min for both epicarp and mesocarp at temperatures of 25°C, 35°C, and 45°C. The removal efficiency of fluoride ions varied from 66.25% (at 25°C) to 77.50% (at 45°C) for the epicarp and from 90% (at 25°C) to 97.50% (at 45°C) for the mesocarp. The thermodynamic parameters of the adsorption process showed that adsorption is a spontaneous, endothermic process for both biosorbents. The adsorption was classified as chemical, with the Langmuir isotherm model best suited to the adsorption isotherms data.

Description: Focusing on the insufficient estimation of the local pressure loss at a 90° horizontal-vertical bend in low-pressure pneumatic conveying of coarse particles, experiments are conducted in a 80 mm inner diameter test bend by using polyethylene particles having an equivalent spherical diameter of 4.00 mm. The influences of the local pressure loss versus the gas flow Reynolds number, the solid-gas ratio, and the bending radius ratio are investigated. Based on the additional pressure theory of Barth, an empirical formula estimating the local pressure loss is obtained using dimensional and nonlinear regression analysis. Summarizing the experiments and literature, the results expound on the local gas flow pressure loss coefficient decreases with increasing Reynolds number, and first decreases and then increases with increasing bending radius ratios from 0.5 to 7. The additional solid flow pressure loss coefficient decreases with the increasing Reynolds number and bending radius ratio in the dilute phase, and linearly increases with increasing solid-gas ratio. Compared with the estimated values with the experimental values, the calculated standard deviation is below 4.11%, indicating that the empirical formula can be used to predict local pressure loss at the bend in the low-pressure dilute-phase pneumatic conveying.

Description: Plate heat exchangers (PHEs) play an important role in different technical fields, namely, in energetics, chemical industry, food industry, and others. To use PHE effectively, it is necessary to have correct data for pressure drop. Unfortunately, in open literature, a large difference among different authors occurs. In this work is shown that an essential portion of this difference lies in the choice of the typical length for the calculation of the friction coefficient. Care must be taken to consider the pressure drop of the distribution zone. A three-component model for hydraulic resistance of PHE in turbulent flow regime is proposed in this work. The proposed model shows good agreement with experimental data.

Description: Ammonium phosphate fire-extinguishing agents are one of the best substitutes for halon in many powder media. Here, 11 μm median diameter ammonium phosphate ultrafine dry powder was used as a fire-extinguishing medium. The fire-extinguishing performance of ultrafine powder under different pressures was studied by analyzing fire-extinguishing time, amount of extinguishing agent, and temperature during the fire-extinguishing process. The results show that the fire-extinguishing performance of the ultrafine powder is improved with increasing injection pressure. Finally, we used FDS software for fire simulation to study the influence of injection pressure on the extinguishing agent. The results show that the extinguishing time is shortened with increasing injection pressure. From 0.2 MPa to 1.0 MPa, the extinguishing time decreases from 34 seconds to 4 seconds.

Description: The present study is aimed at using one of the most promising methods called reactive extraction to extract succinic acid from aqueous solution by using N,N-dioctyloctan-1-amine in biodiesel as diluent made from sunflower oil, rice bran oil, sesame oil, and karanji oil. The results of extraction studies with the diluents (physical) showed their inability to recover any acid by themselves. In reactive extraction, the organic phase extracting power solely depends on tri-n-octylamine. The ranges of the distribution coefficient are found as 7.62–18.12 for sunflower oil biodiesel, 8.33–17.45 for rice bran oil biodiesel, 7.0–17.67 for sesame oil biodiesel, and 9.85–21.36 for karanji oil biodiesel. The ranges of the loading ratio are 0.1–3.0 for sunflower oil biodiesel, 0.1–2.9 for rice bran oil biodiesel, 0.2–2.9 for sesame oil biodiesel, and 0.1–2.9 for karanji oil biodiesel. The karanji and sunflower oil showed higher values of distribution coefficient (KD) over rice bran oil and sesame oil which might be due to presence of both C20 and special fatty acids. The results show that biogenous diluents along with N,N-dioctyloctan-1-amine as extractant form a nontoxic and viable option for the extraction of succinic acid in the binary phase system.