A novel extractant-impregnated resin containing carminic acid for selective separation and pre-concentration of uranium(VI) and thorium(IV)

Abstract

The present work proposes the use of a novel extractant-impregnated resin (EIR) as an adsorbent in trace separation and pre-concentration of U(VI) and Th(IV) ions. The new EIR was prepared by impregnating carminic acid onto Amberlite XAD-16 resin beads. The morphology of new EIR was studied by BET surface area measurements and SEM micrographs. A column packed with CA/XAD-16 was used for selective separation and pre-concentration of the metal ions. Maximum adsorption of Th(IV) and U(VI) ions occurred at pHs of 3.50–5.75 and 3.75–6.50, respectively. The adsorbed metals could be eluted sequentially using 0.55 mol L⁻¹ HCl for U(VI) and 2.25 mol L⁻¹ HCl for Th(IV). The dynamic capacity of EIR was found to be 0.832 and 0.814 mmol g⁻¹ for Th(IV) and U(VI), respectively. The tolerance limit of some foreign ions was also studied. The proposed method showed a good performance in analyzing geological reference materials and a synthetic seawater sample. Furthermore, the above procedure was successfully employed for the analysis of natural water samples.

Keywords:

• extractant-impregnated resin
• U(VI) and Th(IV) separation
• carminic acid
• amberlite XAD-16