Solid phase extraction of trivalent actinides and lanthanides using a novel CMPO-RTIL based chromatographic resin

A novel extraction chromatographic resin was prepared by impregnating CMPO-RTIL (C8mim+·NTf2 −) on Chromosrob-W for the removal of trivalent actinides from aqueous solution and its behaviour was compared with previously reported CMPO-n-dodecane resin. Under identical condition, the K d value of Am(III) by CMPO-RTIL resin (K d at 3 M HNO3 = 5805 ± 525) was one order magnitude higher than that obtained with CMPO-n-dodecane resin (K d at 3 M HNO3 = 610 ± 55). The sorption reaction of Am(III) followed a first-order rate law with both the resins. The metal sorption capacities for Eu(III) at 3 M HNO3 were found to be 18.95 ± 1.13 mg and 20.52 ± 1.25 mg/g of CMPO-RTIL and CMPO-n-dodecane resins, respectively. The analysis of the sorption data by different models supported the hypothesis that the sorption of Eu(III) on the resins was actually limited by the saturation of the CMPO complexing sites on the resin. The free energy for the sorption of Eu(III) obtained from D–R isotherm was 17.67 ± 1.63 kJ/mol and 16.51 ± 2.05 kJ/Mol for CMPO-RTIL and CMPO-n-dodecane resins, respectively. The sorption free energy is an indication of chemisorption monolayer mechanism. The monolayer sorption mechanism was also confirmed by the theoretical approach calculated based on the sorption kinetics.