title: Selective Single-Step Separation of a Mixture of Three Metal Ions by a Triphasic Ionic-Liquid-Water-Ionic-Liquid Solvent Extraction System.
abstract: In a conventional solvent extraction system, metal ions are distributed between two immiscible phases, typically an aqueous and an organic phase. In this paper, the proof-of-principle is given for the distribution of metal ions between three immiscible phases, two ionic liquid phases with an aqueous phase in between them. Three-liquid-phase solvent extraction allows separation of a mixture of three metal ions in a single step, whereas at least two steps are required to separate three metals in the case of two-liquid-phase solvent extraction. In the triphasic system, the lower organic phase is comprised of the ionic liquid betainium- or choline bis(trifluoromethylsulfonyl)imide, whereas the upper organic phase is comprised of the ionic liquid trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide. The triphasic system was used for the separation of a mixture of tin(II), yttrium(III), and scandium(III) ions.
authors.affiliation: Department of Chemistry, KU Leuven, Celestijnenlaan 200F, P.O. Box 2402, 3000 Heverlee (Belgium).
authors.forename: Tom
authors.initials: T
authors.lastname: Vander Hoogerstraete
authors.affiliation: Department of Chemistry, KU Leuven, Celestijnenlaan 200F, P.O. Box 2402, 3000 Heverlee (Belgium).
authors.forename: Jonas
authors.initials: J
authors.lastname: Blockx
authors.affiliation: Department of Chemistry, KU Leuven, Celestijnenlaan 200F, P.O. Box 2402, 3000 Heverlee (Belgium).
authors.forename: Hendrik
authors.initials: H
authors.lastname: De Coster
authors.affiliation: Department of Chemistry, KU Leuven, Celestijnenlaan 200F, P.O. Box 2402, 3000 Heverlee (Belgium). koen.binnemans@chem.kuleuven.be.
authors.forename: Koen
authors.initials: K
authors.lastname: Binnemans
keywords: hydrometallurgy; ionic liquids; rare earths; ternary phase diagram; three-liquid solvent extraction