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Bentonite has been studied extensively because of its strong sorption and complexation ability. In this work, the sorption of Se(IV) on purified GMZ bentonite was investigated under ambient temperature as functions of contact time, pH, Se(IV) concentration and co-existing ion Eu(III) using batch techniques. Sorption kinetics of Se(IV) was successfully described by the pseudo-second-order rate equation. The sorption amount of Se(IV) was strongly dependent on the solution pH, and a positive effect was observed on Se(IV) and Eu(III) co-sorption when these two elements existed in the same system under high surface coverage of sorbent. Double layer model was set up and used to quantitatively interpret the sorption experimental data collected in binary and ternary sorption systems. From the experimental results, one can conclude that GMZ bentonite may have good potentialities for immobilizing selenium in nuclear wastes. [ABSTRACT FROM AUTHOR]

Metal ions sorption can be significantly affected by the presence of other sorbates, especially of complexing ligands. In this study, the effect of Se(IV) on Eu(III) sorption onto TiO at different pH and Eu(III) concentration was investigated. Se(IV) was found to enhance Eu(III) sorption as a function of Se(IV) concentration. Constant capacitance model was successfully used to interpret the sorption experimental data. The solubility product of Eu(SeO) at ambient temperature was investigated to highlight the sorption mechanism of ternary sorption system. The p K value of Eu(SeO) was found to be 31.51 ± 0.95. [ABSTRACT FROM AUTHOR]

Se(IV) sorption on purified Na-kaolinite was investigated under ambient temperature as functions of contact time, pH, ionic strength and Se(IV) concentration using batch techniques. The rate of sorption is relatively rapid and sorption kinetics of Se(IV) can be successfully described by the pseudo-second-order model. The amount of Se(IV) sorbed was moderately dependent on the solution pH but insensitive to ionic strengths. The sorption/desorption isotherms of Se(IV) show that the sorption process is reversible. A double layer model was set up and used to quantitatively interpret the experimental data. Three surface complexes (≡Al)SeO, ≡ AlSeO and ≡AlOHSeO were proposed which satisfactorily fit our data. [ABSTRACT FROM AUTHOR]