Ion exchange studies of Arsenazo-III and thorium(IV) from aqueous solutions of Arsenazo-III with AG-2×8, Dowex-50 W×8 and Chelex-100

Abstract

The sorption behavior of Th(IV) from intermediate acidic solutions (0.5–1.5N HCl) of Arsenazo-III with three different types of ion exchangers, namely Dowex-50 W×8, AG-2×8 and Chelex-100 is studied at different concentrations of Arsenazo-III corresponding to metal: reagent ratio of 1∶1 to 1∶3. The sorption behavior of Arsenazo-III with AG-2×8 and Chelex-100 under various experimental conditions is studied as well. Complete sorption of the reagent on AG-2×8 under all studied conditions is found. The sorption process from solutions at high pH-values is found to be relatively slow. Complete sorption of reagent on Chelex-100 is found from acidic solutions. The percent uptake decreases sharply with increasing pH value. While partial sorption of Th(IV) or Th(IV)-Arsenazo-III complexes on Dowex-50 W×8 or AG-28, respectively, is found, Chelex-100 is found to be selective for concentrating thorium as coloured Arsenazo-III complex which may be useful in ion exchange phase absorptiometry. The sorbed complex from 0.5N HCl solutions of Arsenazo-III is proved to be ThL.