REMOVAL OF SELENIUM AND ANTIMONY SPECIES FROM AQUEOUS SOLUTIONS BY MEANS OF A WEAKLY BASIC ION EXCHANGER

Abstract

The removal of Se(IV), Se(VI), Sb(III) and Sb(V) from aqueous solutions by ion exchange using the commercially available weakly basic anion exchanger Duolite A7 with secondary amino groups has been investigated. This work comprises investigations of the equilibria of the sorption of Se and Sb and of the kinetics of uptake. The efficiency of sorption of selenium and antimony species depend strong on the pH. Se(IV) is well sorbed in a narrow range between pH 2.5 and 5.5 whereas Se(VI) is well sorbed between pH = 1 and 6. Sb(III) shows a maximum sorption between pH = 1 and 7, and for Sb(V) optimum sorption is obtained for pH < 5. The kinetic studies show that Se(VI) was removed almost completely in 20 min while sorption of the other species developed slowlier. Studies on sorption equilibria from pure solutions revealed the highest exchanger loadings for Se(VI) and smaller ones for the other species.