Removal of 241Am from aqueous nitrate solutions by liquid surfactant membrane containing 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester as ion carrier

A liquid surfactant membrane (LSMs) containing 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (H2A2) was tested for the extraction of americium(III) from aqueous nitrate solutions of different compositions. Span 80 a surface-active agent and 0.5 M HNO3 were used as emulsion stabilizer and internal phase respectively in the LSM system. Influence of some important experimental parameters such as pH of the exterior phase, ionic impurities in the exterior phase, concentration of H2A2 and Span 80 in liquid membrane phase on the LSM permeation process was systematically studied. The maximum efficiency of Am(III) extraction among group of experiments was 93 ± 2% with modified permeability coefficient = 1.21 ± 0.02 min−1 and the corresponding concentration factor of Am(III) in the receiving phase was 10.5 ± 0.2. Extraction of commonly associated fission product elements such as 137Cs, 152,154Eu, 90Sr, 95Zr, 144Ce, 95Nb and 103Ru was also investigated from feed solution in the exterior phase adjusted at different pH. In a single batch of extraction, more than 90% removal and about 10 times concentration of Am(III) was obtained from uranium and plutonium depleted (process of Plutonium Uranium Recovery by Extraction) waste solution. A complete demulsification of metal loaded emulsion was obtained by chemical using 2-ethylhexanol and physical using freeze thaw method.