Sorption properties of oxides. IV. Hydrous mixed oxides

Anion sorption of hydrous oxides can be enhanced by suitably substituting the metal ion in an oxide matrix with a metal ion of higher charge. These mixed oxides will behave as anion sorbers in neutral and alkaline media as a result of induced anion sorption ability. Hydrous mixed oxides, Bi(III)-Ti(IV), Bi(III)-Zr(IV), Bi(III)-Th(IV), Ti(IV)-Sb(V), and Zr(IV)-Sb(V), have been prepared and sorption of some anions by them was tested under acidic, neutral, and alkaline conditions and the behavior compared with that of pure oxides. Results indicated that the sorption properties of mixed oxides depend very much on the nature and composition of the final product. Among the different mixed oxides studied, Bi(III)-Th(IV) mixed oxide exhibited very good sorption for Cl<SUP>-</SUP> and I<SUP>-</SUP> ions even in alkaline medium