Effect of complexants on the adsorption and color reactions of lanthanum(III), uranium(VI), thorium(IV), and zirconium(IV) with Arsenazo M in the solid phase of an ANKB-50 fibrous ion-exchanger

The effect of complexants—acetic, aminoacetic, tartaric, malonic, and oxalic acids; EDTA; and Na₂CO₃—on the adsorption and subsequent determination of thorium(IV), lanthanum(III), uranium(VI), and zirconium(IV) with Arsenazo M in the solid phase of polyacrylonitrile fiber filled with an ANKB-50 anion exchanger was studied. Complexing agents were introduced into the solution at the step of metal ion adsorption. It was shown that zirconium and uranium interacted with the iminodiacetate groups of the adsorbent in the course of adsorption; the adsorption of elements from 10^?3 to 10^?2 M complexant solutions (except for tartaric and oxalic acids and EDTA) under the optimum conditions was enhanced as compared to their adsorption from pure solutions; complexation with Arsenazo M in the solid phase proceeded at a higher acidity than in the solution. When the elements were present simultaneously, their total concentration and individual thorium could be determined from malonic acid solutions with Arsenazo M by varying the concentration of acid and the adsorption pH.