Extraction and sorption preconcentration of U(VI) and Th(IV) from nitric acid solutions using bis(diphenylphosphorylmethylcarbonylamino)alkanes

Abstract

Extraction of microamounts of U(VI) and Th(IV) from HNO3 solutions in the form of complexes with polyfunctional neutral organophosphorus compounds, bis(diphenylphosphorylmethylcarbonylamino)alkanes [Ph2P(O)CH2C(O)NH]2(CH2)n (n = 3, 5, 8), was studied. The influence of the extractant structure on the efficiency and selectivity of the extraction of U(VI) and Th(IV) was examined, and the stoichiometry of the extractable complexes was determined. The examined compounds exhibit higher extraction ability and selectivity to metal ions in HNO3 solutions, compared to the alkylamide Ph2P(O)CH2C(O)NHC9H19. The possibility of selective recovery and preconcentration of U(VI) and Th(IV) from nitric acid solutions with a complexing sorbent prepared by noncovalent immobilization of bis(diphenylphosphorylmethylcarbonylamino)pentane on a macroporous polymeric matrix was demonstrated.