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A Novel Mechanism for the Extraction of Metals from Water to Ionic Liquids

Authors

  • Dr. Camiel H. C. Janssen,

    1. Department of Biotechnology, Faculty of Applied Sciences, TU Delft, Julianalaan 67, 2628 BC, Delft (The Netherlands)
    2. Wetsus Centre of Excellence for Sustainable Water Technology, Agora 1, 8900 CC, Leeuwarden (The Netherlands)
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  • Dr. Antonio Sánchez,

    1. Department of Chemistry, Brooklyn College of the City University of New York, 2900 Bedford Ave., Brooklyn, NY 11210 (USA)
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  • Prof. Geert-Jan Witkamp,

    1. Department of Biotechnology, Faculty of Applied Sciences, TU Delft, Julianalaan 67, 2628 BC, Delft (The Netherlands)
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  • Prof. Mark N. Kobrak

    Corresponding author
    1. Department of Chemistry, Brooklyn College of the City University of New York, 2900 Bedford Ave., Brooklyn, NY 11210 (USA)
    2. Department of Chemistry, The Graduate Center of the City University of New York, 365 Fifth Ave., New York, New York 10016 (USA)
    • Department of Chemistry, Brooklyn College of the City University of New York, 2900 Bedford Ave., Brooklyn, NY 11210 (USA)

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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.

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