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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 25 (1996), S. 257-265 
    ISSN: 1573-1111
    Keywords: Crown ethers ; nitrobenzene ; plutonium (IV) ; solvent extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Ion-pair extraction behaviour of plutonium (IV) from varying concentrations of HCl solution was studied employing crown ethers (benzo-l5-crown-5 (B15C5), 18-crown-6, (18C6), dibenzo-18-crown-6 (DB18C6), dicyclohexano-18-crown-6, (DC18C6), dibenzo-24-crown-8 (DB24C8) and dicyclohexano-24-crown-8 (DCH24C8)) in nitrobenzene as the extractant. Ammonium metavanidate was used as the holding oxidant in the aqueous phase and the conditions necessary for the quantitative extraction of the tetravalent ion were found. The co-extraction of species of the type [HL+].[HPu(Cl) 6 − ] and [HL+]2·[Pu(Cl) 6 2− ] as ion-pairs (where L represents the crown ether) is suggested.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 139 (1990), S. 223-229 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Several adducts of U(IV) and Th(IV) with 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedione (FOD) as β-diketone and a variety of neutral oxodonors were synthesized and characterized by visible spectral, proton magnetic resonance as well as thermogravimetric studies. Adducts with dimethylformamide (DMF) were found to be most volatile, whereas with trioctylphosphine oxide (TOPO) were quite susceptible towards decomposition.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 15 (1993), S. 121-130 
    ISSN: 1573-1111
    Keywords: Americium ; tris-bipyridine cryptand ; extraction ; dinonylnaphthalene sulphonic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Complexation of Am(III) with a tris-bipyridine cryptand (L) has been carried out in a nonaqueous medium (CH3CN−CHCl3). Subsequently the complexation behaviour was investigated using the reverse extraction tracer technique with dinonyl naphthalenesulphonic acid (HD) in toluene as the organic phase and varying concentration of HCl (upto 2M) as the aqueous phase. Equilibrium is attained in the two-phase system at a rate dependent on the hydrogen ion concentration in the aqueous phase. Whereas it takes only a few minutes to attain the equilibrium state at pH 6.0, a phase contact period of 50 days was insufficient if the acidity is greater than 0.4M, presumably due to the slow dissociation of the cryptate formed. The large enhancement in the distribution ratio value in the synergistic system with 1M HCl as the aqueous phase under non-equilibrium conditions is employed for the analytical separation of Am(III) from Eu(III).
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 240 (1999), S. 159-164 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The role of temperature on the distribution of Am3+ and UO2 2+ was investigated in the extraction systems involving TBP and DOSO as the neutral oxodonors and picrate as the organophilic counter anion. The inner-sphere water molecules and their substitution by the oxodonor molecules appeared to influence the extraction constants of these metal ions. The conditional extraction constants for Am3+ were found to be larger (about 3 order of magnitude) than those for UO2 2+. From the thermodynamics data it appeared that both TBP as well as DOSO bind Am3+ ion through outer-sphere coordination. In presence of 1M NaCl, though the interaction with TBP remains unaltered DOSO tend to form an inner-sphere complex. On the other hand, UO2 2+ forms inner-sphere complexes with DOSO and outer-sphere complex with TBP in the absence of salt. In the presence of 1M NaCl, both TBP and DOSO form inner-sphere complexes. The effect of ionic strength on metal ion extraction was also investigated.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 83 (1984), S. 301-307 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Octylphenyl acid phosphate, the commercially available mixture of monooctylphenylphosphoric acid (MOPPA) and dioctylphenylphosphoric acid (DOPPA) in xylene medium has been employed as an extractant for distribution studies on Pu(IV) in different mineral acids including phosphoric acid. It was found possible to extract Pu quantitatively from an acid mixture comprising 2.5M H3PO4, 0.75M H2SO4 and 0.5M HNO3. Quantitative stripping was observed with a mixture of 0.25M oxalic acid and 0.2M ammonium oxalate.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 242 (1999), S. 627-634 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The extraction behavior of several metal ions viz., Am3+, Eu3+, UO2 2+, Th4+, Sr2+ and Cs+ was investigated from sulphate medium employing phosphotungstic acid (PTA) and polyethylene glycol (PEG). The influence of various parameters such as pH, PTA concentration, PEG concentration and salt concentration was studied. The order of extraction followed the trend: Am3+〉Eu3+〉〉Th4+〉UO2 2+〉Sr2+〉Cs+ which deviate significantly from the reported order with conventional solvents. The relatively poor extraction of UO2 2+, Sr2+ and Cs+ was ascribed to their lack of interaction with the phosphotungstate anion. The separation behaviour of Am3+ vis-a-vis Eu3+ was also investigated under different experimental conditions.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 240 (1999), S. 31-38 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The extraction behavior of Th(IV) from dilute nitric as well as perchloric acid medium using 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) and its mixture with tri-n-octyl phosphine oxide (TOPO) was investigated. The species of the type Th(X)(PMBP)3·(HPMBP) and Th(X)(PMBP)3·(TOPO) were extracted for the binary and ternary extraction systems, respectively, where X=NO3− or ClO4−. The presence of 1.25·10−5M Th carrier in the aqueous phase resulted in the extracted species of the type of Th(PMBP)4 and Th(PMBP)4·(TOPO), respectively. The extraction constant (logk ex ) for the binary species Th(PMBP)4 was found to be 6.89±0.01 while the overall extraction constant (logK) for the ternary species Th(PMBP)4·(TOPO) was calculated to be 13.17±0.06.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 241 (1999), S. 101-105 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The extraction behavior of Am3+ and UO2 2+ is investigated employing chloroform solution of 18-crown-6 as the organic phase and picrate solution at pH 3.0 as the aqueous phase. In contrast to the commonly observed behavior, the extraction of Am3+ is preferred to that of UO2 2+. This unusual separation behavior is investigated as a function of several variable parameters such as crown ether concentration, picric acid concentration, inert electrolyte concentration, nature of diluent etc. Thermodynamic parameters are also evaluated.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 156 (1992), S. 215-221 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract With increasing global nuclear activities, there is a growing interest in understanding the migration behavior of transuranic elements in the terrestrial environment. The laboratory investigations on the adsorption behavior of AM(III) (∼10−7M) in aqueous solutions showed that there was not adsorption of Am(III) on glass or polyethylene vials from aqueous solutions at pH〈3. The rate of adsorption was found to be inversely related to the (H+) in the pH range 4–7. It was also found to be strongly influenced by stirring/shaking as well as by the presence of particulate matter in the aqueous phase. The presence of particulate matter (〉0.6 μm) in the aqueous solutions significantly inhibits the adsorption rate. Attempts to fit the kinetic data (collected on filtered [particle size 〉0.6 μm] or unfiltered distilled water at pH 6) to the reversible or irreversible first order rate equation did not successfully indicate the complexity of the adsorption process. The presence of ∼20mg/liter of humic acid at pH 6.3 completely inhibits the adsorption of Am on glass surfaces.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 229 (1998), S. 169-172 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Extraction behavior of137Cs was studied from nitric acid medium using dibenzo 18 crown 6 (DB18C6), 4,4'(5')di-acetylbenzo 18 crown 6 (DAB18C6), 4, 4'(5')di-hexanoylbenzo 18 crown 6 (DHB18C6), 4,4'(5')di-nonanoylbenzo 18 crown 6 (DNB18C6) and 4,4'(5')di-t-butylbenzo 18 crown 6 (DTBB18C6) in nitrobenzene medium. The stoichiometry of the species extracted with dibenzo 18 crown 6 (L) conformed to ML+. NO3 − TheD Cs values were found not to be affected by the presence of aluminium nitrate in the aqueous phase. The separation behavior of fission products obtained from an irradiated natural uranium target was also studied. Presence of 0.004M phosphotungstic acid found to enhance theD Cs values at lower acidities.
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