Di-[trioctyl-(8-phenyloctyl)-phosphonium] pamoate: synthesis and characterization of a novel, highly hydrophobic ionic liquid for the extraction of scandium, thorium and uranium

Author(s)
Andreas Gradwohl, Jakob Windisch, Alexander Rosner, Julia Heninger, Philipp L. Fuhrmann, Gabriele Wallner, Bernhard K. Keppler, Wolfgang Kandioller, Franz Jirsa
Abstract

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 h. 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 h. 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.

Organisation(s)
Department of Inorganic Chemistry
External organisation(s)
University of Natural Resources and Life Sciences, University of Johannesburg (UJ)
Journal
Frontiers in Chemistry
Volume
12
ISSN
2296-2646
DOI
https://doi.org/10.3389/fchem.2024.1502232
Publication date
2024
Peer reviewed
Yes
Austrian Fields of Science 2012
104003 Inorganic chemistry, 204001 Inorganic chemical technology
Keywords
ASJC Scopus subject areas
General Chemistry
Portal url
https://ucrisportal.univie.ac.at/en/publications/b33b2b6e-c82d-4490-bb17-96b2f010f086