Ionic liquid-salt based aqueous biphasic system for separation of 109Cd from silver target

Aqueous biphasic system (ABS) is greener alternative to the conventional liquid liquid extraction as ABS does not involve any organic or volatile reagents. Generally ABS systems are composed of polymer and salt rich phases. In this paper a new ABS system is proposed replacing polymer rich phase by water soluble room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium Chloride ([bmim]Cl) and kosmotropic salt K2HPO4. The system has been applied to separate the no-carrier-added (NCA) Cd-109 (T (1/2) = 462.6 days) from the alpha-particle irradiated bulk Ag target. The optimum separation condition was achieved with the addition of 6 M HNO3 to the ABS, where similar to 87 % of the bulk Ag was extracted in the IL phase, leaving similar to 96 % NCA Cd-109 in the salt rich phase. The salt rich phase was re-extracted twice with the RTIL to free from bulk Ag. This process achieved an overall separation of 91 % NCA Cd-109 free from bulk Ag. The developed method demonstrates minimum requirement of RTIL to carry out the separation. The method is environmentally benign and cost effective.