Removal of radioselenium oxyanions from aqueous solutions by adsorption onto hydrous zirconium oxide

Adsorption of Se-75(IV) oxyanions onto hydrous zirconium oxide (HZO) is investigated. At pHs 2.2 and 5.3, most of Se(IV) are removed within 5 min and the equilibrium is attained at 40 min. Kinetic and equilibrium data are analyzed by several kinetic and isotherm models, respectively. Adsorption of Se(IV) at different pHs (1.5-12) is dependent on its initial concentration. HZO exhibited a high adsorption capacity for Se(IV), Q (max) = 213.19 mg/g, which is higher than those reported for other adsorbents. Thermodynamic studies revealed that the present adsorption process is feasible, spontaneous and endothermic. Adsorption of Se(IV) in presence of foreign anions is also evaluated.