Extraction of Lanthanides(III) with N,N′-Bis(Diphenylphosphinyl-Methylcarbonyl)Diaza-18-Crown-6 in the Presence of Ionic Liquids

Abstract

The extraction of microquantities of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y from nitric acid solutions into an organic phase containing N,N′-bis(diphenylphosphinyl-methylcarbonyl)diaza-18-crown-6 and ionic liquid (IL) 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide (BMImTf2N) has been studied. The effect of HNO3 concentration in the aqueous phase and that of the extractant and IL concentration in the organic phase on the extraction of metal ions is considered. The stoichiometry of the extracted complexes has been determined. A considerable synergistic effect was observed in the presence of IL in the organic phase containing a neutral organophosphorus ligand. This effect is connected with the hydrophobic nature of the IL anion. The partition of IL between the equilibrium organic and aqueous phases is the dominant factor governing the extractability of lanthanide (III) ions in the extraction system. The potentialities of polymeric resin impregnated with compound I and BMImTf2N for the preconcentration of lanthanides(III) from nitric acid solutions are demonstrated.