Insights into the extraction behavior of U(VI) in Aliquat-336 based ionic liquids

Abstract

Abstract The extraction behavior of U(VI) in the PUREX solvent namely 1.1 M tri-n-butyl phosphate (TBP) in n-dodecane (n-DD) was studied in the presence and absence of the ionic liquid, tri-n-octylmethylammonium bis-(2-ethylhexyl)phosphate ([A336]+ [DEHP] – ). The discrepancy in the extraction behavior observed in these systems was probed by measuring the distribution ratio of U(VI) as a function of various parameters. The distribution ratio of U(VI) in 0.03 M [A336]+ [DEHP] – /n-DD decreased with increase in the concentration of nitric acid. The extraction of U(VI) was accompanied by the extraction of nitric acid leading to the formation of ionic liquid constituents namely tri-n-octylmethylammonium nitrate ([A336]+ [NO3] – and bis(2-ethylhexyl)phosphoric acid (HDEHP). Therefore, the distribution ratio of U(VI) in the PUREX solvent was measured in the presence of these constituents also. The study revealed that extraction of U(VI) was controlled essentially by the synergistic contribution of TBP and the constituents of ionic liquid.