Solvent extraction studies of Pu(IV) with CMPO in 1-octyl 3-methyl imidazolium hexa fluorophosphate (C8mimPF6) room temperature ionic liquid (RTIL)

Solvent extraction studies of Pu(IV) from aqueous nitric acid by carbamoyl methyl phosphine oxide (CMPO) in 1-octyl 3-methyl imidazolium hexa fluorophosphate (C8mimPF6) room temperature ionic liquid (RTIL) were carried out. It was inferred that the stoichiometry of the Pu(IV) species extracted into RTIL phase, through cation exchange mechanism, is [Pu(NO3)(CMPO)x]-3 where x varies from 1 to 2 under the experimental conditions used. Thermodynamic parameters showed the extraction to be favoured by negative enthalpy change, but counteracted by negative entropy change. (orig.)