Recovery of radionuclides with ionic liquids. I. Selective extraction of 241Am

Abstract

1-methyl-3-octylimidazolium saccharinate {[C8C1im][Sac]} – a hydrophobic but polar ionic liquid (IL) capable of capturing and liberating water in a controllable manner was employed as an extraction phase in the liquid–liquid extraction for the recovery of radioactive elements (241Am, 137Cs and 60Co) from aqueous solutions. The influence of factors such as IL/aqueous source ratio, pH and presence of complex-forming agents (citric acid, oxalic acid) on the extraction yield was comprehensively studied. The radionuclides were shown to possess different behavior under the same conditions, the latter being attributed, and further proved by theoretical speciation analysis, to the formation of species capable of interacting in a specific manner with the IL-phase. The results obtained showed the possibility for controllable and selective transfer between the IL and aqueous phases and resulted in the development of a simple procedure for extraction and concentration of 241Am. The method developed proved successful in the monitoring of this radionuclide in drinking water samples.