Sorption of europium(III) on polymeric silica in perchlorate media

Abstract

Sorption of europium, Eu(III) with polymeric silicic acid has been studied under varying experimental conditions such as pH, ionic strength (I), concentration of silicic acid and of Eu(III), the presence of carbonate ions, and aging time. Sorption studies of Eu(III) at pH 7.50 ± 0.50) andI= 0.20 M NaClO4indicate 1.32 ± 0.06 × 10-5M Eu as the Critical Coagulation Concentration, CCC. Sorption of Eu(III) on colloidal silica increases with increased ionic strength from 80% (0.20 M NaClO4) to 93% (0.89 M NaClO4). The coagulation process is favored by an increase in silica concentration. The influence of CO32-(1.00 × 10-3M) on the reaction of Eu(III) with polysilicic acid was negligible in the pH range 7.0 to 9.0. Dissolved Eu3+binds more strongly to the silicate polymers than do Cs+and Cu2+.