Separation of Am3+ and Eu3+ using an extraction chromatographic resin containing bis(2,4,4-trimethylpentyl)dithiophosphinic acid as the stationary phase

Sorption of Am3+ and Eu3+ onto an extraction chromatographic resin material, prepared by impregnating purified bis(2,4,4-trimethylpentyl)dithiophosphinic acid (commercially available as Cyanex 301) into Chromosorb W, was investigated. Separation factor (S.F. = Kd,Am/Kd,Eu) values tend to increase in the presence of complexing agents such as thiocyanate and nitrate. In presence of 1 M NaNO3 in the aqueous phase, a S.F. value of ∼1000 was obtained. The nature of extracted species was ascertained by carrying out the sorption studies at different aqueous phase pH. A column made from 300 mg of the resin material was used for the separation of Am3+ and Eu3+. A synthetic solution containing 1 × 105 cpm each of Am3+ and Eu3+ when loaded on to the column, >99% Eu was eluted out in 60 mL of 1 M NaNO3 at a pH of 3.2 while Am was eluted out using 5 mL of 1 M HNO3. The performance of the resin material was found to be reasonably good even after three cycles.