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ORIGINAL RESEARCH article

Front. Chem.
Sec. Molecular Liquids
Volume 12 - 2024 | doi: 10.3389/fchem.2024.1502232
This article is part of the Research Topic Intermolecular Interaction Studies in Binary and Higher Order Liquid Mixtures, Ionic Liquids and Deep Eutectic Solvents (DES) Based Systems View all articles

Di-[trioctyl-(8-phenyloctyl)-phosphonium] pamoate: Synthesis & Characterization of a novel, highly hydrophobic Ionic Liquid for the Extraction of Scandium, Thorium & Uranium

Provisionally accepted
Andreas Gradwohl Andreas Gradwohl 1Jakob Windisch Jakob Windisch 1Alexander Rosner Alexander Rosner 1Julia Heninger Julia Heninger 1Philipp L. Fuhrmann Philipp L. Fuhrmann 2Gabriele Wallner Gabriele Wallner 1Bernhard K. Keppler Bernhard K. Keppler 1Wolfgang Kandioller Wolfgang Kandioller 1Franz Jirsa Franz Jirsa 1*
  • 1 Institute of Inorganic Chemistry, University of Vienna, Vienna, Austria
  • 2 University of Natural Resources and Life Sciences Vienna, Vienna, Vienna, Austria

The final, formatted version of the article will be published soon.

    We synthesized and characterized a novel, task-specific ionic liquid for metal extraction with considerably reduced leaching behavior compared to similar, phosphonium-based ionic liquids. The synthesis involves the design of the novel compound [TOPP]2[PAM] featuring both a highly hydrophobic cation and a functional anion. The characterization of the novel ionic liquid confirmed the formation of the desired structure and sufficient purity. The high viscosity of [TOPP]2[PAM] is responsible for the comparably high working temperature of 50°C. Extraction experiments demonstrated the suitability of [TOPP]2[PAM] for extracting Sc, Th and U from aqueous matrices, whereby extraction efficacies of 87.3 ± 9.1 % (Sc), 95.8 ± 2.3 % (Th) and 92.7 ± 0.3 % (U) were achieved over 24 hours. Furthermore, Sc could be separated to a high degree via selective extraction from Th as well as from the rare earth elements Y, La, Ce, Nd, Eu, Ho and Lu. Th was separated from La, Ce, Nd, Eu, Ho and Lu at pH 1.00. During all extraction experiments, leaching into the aqueous extraction matrix peaked at only 0.134 ± 0.011 % after 24 hours. The loading capacities for [TOPP]2[PAM] differed between the investigated metals, the highest values being achieved for U. After extraction, 82.7 ± 2.8 % of the extracted Sc could be recovered from the IL using nitric acid (10 %), but less of Th and U.

    Keywords: Ionic Liquid, task-specific, Selective extraction, REE separation, Leaching, Green solvents

    Received: 26 Sep 2024; Accepted: 04 Nov 2024.

    Copyright: © 2024 Gradwohl, Windisch, Rosner, Heninger, Fuhrmann, Wallner, Keppler, Kandioller and Jirsa. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Franz Jirsa, Institute of Inorganic Chemistry, University of Vienna, Vienna, 1090, Austria

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