Europium(III) complexation behaviour in an alkyl ammonium ionic liquid medium containing neutral extractants

An alkyl ammonium based ionic liquid, methyltributylammonium bis(trifluoromethylsulfonyl)imide ([N-1444] [NTf2]), has been explored as a diluent and studied for the extraction of Eu(III) in conjunction with a couple of neutral extractants namely N,N,N',N'-tetra(2-ethylhexyl)diglycolamide (T2EHDGA) and octylphenyl (N,N-dii-sobutyl)carbamoylmethylphosphinoxide (CMPO) from nitric acid medium. The extraction behavior of Eu(III) was investigated as a function of various extraction parameters such as feed acidity, concentration of extractant, concentration of metal ion in the aqueous phase etc. The extraction stoichiometry of the metal-solvate (Eu:extractant ratio) in ionic liquid medium was determined and the aggregation behavior of the metal-solvate in ionic liquid phase was investigated by dynamic light scattering (DLS), Attenuated Total internal Reflection-Fourier Transformation infra-red (ATR-FTIR) and luminescence spectroscopy. The radiolytic stability of the ionic liquid phase containing T2EHDGA and CMPO was assessed by irradiating the ionic liquid phase to various absorbed dose levels and determining the distribution ratio of Eu(III) in the irradiated phase.