ION-EXCHANGE STUDIES OF ARSENAZO-III AND THORIUM(IV) FROM AQUEOUS-SOLUTIONS OF ARSENAZO-III WITH AG-2X8, DOWEX-50 WX8 AND CHELEX-100

The sorption behavior of Th(IV) from intermediate acidic solutions (0. 5-1.5N HCl) of Arsenate-III with three different types of ion exchange rs, namely Dowex-50 W x 8, AG-2 x 8 and Chelex-100 is studied at diffe rent concentrations of Arsenate-III corresponding to metal: reagent ra tio of 1:1 to 1:3. The sorption behavior of Arsenazo-III with AG-2 x 8 and Chelex-100 under various experimental conditions is studied as we ll. Complete sorption of the reagent on AG-2 x 8 under all studied con ditions is found. The sorption process from solutions at high pH-value s is found to be relatively slow. Complete sorption of reagent on Chel ex-100 is found from acidic solutions, The percent uptake decreases sh arply with increasing pH value. While partial sorption of Th(IV) or Th (IV)-Arsenazo-III complexes on Dowex-50 W x 8 or AG-28, respectively, is found, Chelex-100 is found to be selective for concentrating thoriu m as coloured Arsenate-III complex which may be useful in ion exchange phase absorptiometry. The sorbed complex from 0.5N HCl solutions of A rsenate-III is proved to be ThL.