Sorption of 90Sr onto Manganese Oxides Prepared in Aqueous-Ethanol Media

Abstract

Sorbents based on manganese oxides were prepared by KMnO₄ reduction in aqueous-ethanol medium. The influence of the synthesis conditions (temperature and time of the sol-gel synthesis, type of structure-forming cations, calcination temperature) on the pore structure and on the performance and selectivity in ⁹⁰Sr sorption was studied. The sorbents have the mesoporous structure with the specific surface area of 180–220 m² g⁻¹ and mean pore size of 10–20 nm. Manganese oxide of channel structure in the Na⁺ form, prepared by the reaction at 25°C for 5 h and heat-treated at 350°C, exhibits the highest performance and selectivity in ⁹⁰Sr sorption (distribution coefficient K_d = 1.04 × 10⁴ cm³ g⁻¹, Sr-Ca separation factor D_Sr/Ca = 99). The sorbents synthesized exhibit the highest performance and selectivity in neutral and alkaline media.