Extraction of lanthanides from aqueous solution by using room-temperature ionic liquid and supercritical carbon dioxide in conjunction

Abstract

For the first time, the study of a three-step extraction system of water/ionic liquid/supercritical CO2 has been performed. Extraction of trivalent lanthanum and europium from an aqueous nitric acid solution to a supercritical CO2 phase via an imidazolium-based ionic liquid phase is demonstrat ed, and extraction efficiencies higher than 87 % were achieved. The quantitative extraction is obtained by using dif ferent fluorinated β-diketones with and without the addition of tri(n-butyl)-phosphate. The complexation phenomenon occurring in the room-temperature ionic-liquid (RTIL) phase was evidenced by using luminescence spectroscopy. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA.