Application of the de Job method in the evaluation of the stoichiometry of uranyl phosphate complexes sorbed on bentonite
Open Access
- 31 March 2016
- journal article
- Published by European Journal of Chemistry in European Journal of Chemistry
- Vol. 7 (1), 42-48
- https://doi.org/10.5155/eurjchem.7.1.42-48.1348
Abstract
For the first time, the continuous variation method was applied for the evaluation of the stoichiometry of uranyl phosphate complexes sorbed on bentonite. Sorption of UO2(CH3COO)2⋅2H2O in the presence of Na2HPO4⋅7H2O from 0.001 mol/L solutions led to the appearance of maxima in the sorption peaks of U(VI) and P(V) ions at molar ratios of [U(VI)]/[P(V)]s = 1.4, 3.3, 3.6 and 1.2, 1.7. It is suggested, based on complementary XRD and XPS data, that the UO2HPO4 complex is located on aluminols (ºAl-OH) whereas the (UO2)3(PO4)2⋅4H2O complex is precipitated in the interlamellar space of bentonite. The participation of (UO2)3(OH)5+ and (UO2)4(OH)7+ species in the formation of U(VI) surface complexes is suggested, based on the deconvolution of sorption spectra of U(VI) on the bentonite in the presence of phosphates.Keywords
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