Incorporation of selenium(IV) and selenium(VI) on uranyl peroxide

The sorption of Se(IV) and Se(VI) on uranium peroxide has been studied considering the sorption kinetics, the sorption isotherms and the effect of pH. Selenium sorption on studtite is fitted with a pseudosecond order reaction model; in addition, two different mechanisms seem to influence the sorption process: micropore diffusion and intra-particle diffusion. Both selenium(IV) and selenium(VI) are sorbed on studtite through a monolayer coverage. Sorption is higher at acidic pH than at alkaline pH. This behaviour is consistent with the chemical speciation of selenium in solution and with the acid–base properties of the solid.