title: A novel mechanism for the extraction of metals from water to ionic liquids.
abstract: We present a novel mechanism for the extraction of metals from aqueous phases to room-temperature ionic liquids (ILs) by use of a high-temperature salt as an extraction agent. The mechanism capitalizes on the fact that charged metal complexes are soluble in ILs; this allows for extraction of charged complexes rather than the neutral species, which are formed by conventional approaches. The use of a well-chosen extraction agent also suppresses the competing ion-exchange mechanism, thus preventing degradation of the ionic liquid. The approach permits the use of excess extractant to drive the recovery of metals in high yield. This work presents both a thermodynamic framework for understanding the approach and experimental verification of the process in a range of different ILs. The method has great potential value in the recovery of metals, water purification and nuclear materials processing.
authors.affiliation: Department of Biotechnology, Faculty of Applied Sciences, TU Delft, Julianalaan 67, 2628 BC, Delft (The Netherlands); Wetsus Centre of Excellence for Sustainable Water Technology, Agora 1, 8900 CC, Leeuwarden (The Netherlands).
authors.forename: Camiel H C
authors.initials: CH
authors.lastname: Janssen
authors.forename: Antonio
authors.initials: A
authors.lastname: Sánchez
authors.forename: Geert-Jan
authors.initials: GJ
authors.lastname: Witkamp
authors.forename: Mark N
authors.initials: MN
authors.lastname: Kobrak
mesh_terms: D002623:Chemistry Techniques, Analytical; D056831:Coordination Complexes / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry*; D008670:Metals / Q000737:chemistry* / Q000302:isolation & purification*; D012995:Solubility; D014867:Water / Q000737:chemistry*; D018508:Water Purification
chemical_list: D056831:Coordination Complexes; D052578:Ionic Liquids; D008670:Metals; D014867:Water
keywords: crown compounds; ion chromatography; ion exchange; ionic liquids; thermodynamics