Extraction of rare earth elements from aqueous solutions using the ionic liquid trihexyltetradecylphosphonium 3-hydroxy-2-naphthoate.

Autor:	Gradwohl A; Department of Inorganic Chemistry, University of Vienna Währinger Straße 42 Vienna 1090 Austria franz.jirsa@univie.ac.at., Windisch J; Department of Inorganic Chemistry, University of Vienna Währinger Straße 42 Vienna 1090 Austria franz.jirsa@univie.ac.at., Weissensteiner M; Department of Inorganic Chemistry, University of Vienna Währinger Straße 42 Vienna 1090 Austria franz.jirsa@univie.ac.at., Keppler BK; Department of Inorganic Chemistry, University of Vienna Währinger Straße 42 Vienna 1090 Austria franz.jirsa@univie.ac.at., Kandioller W; Department of Inorganic Chemistry, University of Vienna Währinger Straße 42 Vienna 1090 Austria franz.jirsa@univie.ac.at., Jirsa F; Department of Inorganic Chemistry, University of Vienna Währinger Straße 42 Vienna 1090 Austria franz.jirsa@univie.ac.at.; Department of Zoology, University of Johannesburg PO Box 524, Auckland Park Johannesburg 2006 South Africa.
Jazyk:	angličtina
Zdroj:	RSC advances [RSC Adv] 2023 Aug 21; Vol. 13 (36), pp. 24899-24908. Date of Electronic Publication: 2023 Aug 21 (Print Publication: 2023).
DOI:	10.1039/d3ra03967f
Abstrakt:	The task-specific ionic liquid trihexyltetradecylphosphonium 3-hydroxy-2-naphthoate has been described as a suitable extraction agent for numerous metals from aqueous phases, while additionally providing reduced leaching into the used matrices. Here, we investigate the extraction properties of this extractant towards rare earth elements. Of these, La, Ce, Nd, Ho und Lu were chosen as a representative mix of light and heavy elements. Single- as well as double-element extractions were carried out under varying conditions regarding pH, temperature and extraction time. The highest extraction efficacies and minimalized precipitation of the respective metals were recorded at a pH of 2.5. Satisfactory extraction efficacies (>80%) were achieved already after 6 hours for the elements Ce, Nd and Lu in single-element extraction experiments at room temperature. Increased temperatures improved the extraction efficacy for Nd from 36% at 20 °C to 80% at 30 °C after only 2 hours. Surprisingly, this effect was not observed for Ce in single-element experiments. In double-element feed solutions containing both Ce and Nd, however, the time-dependant extraction efficacy of Ce mirrored that of Nd. The pH in the aqueous extraction matrix changed during the extraction, showing a positive correlation with the extraction efficacy and revealing the extraction mechanism to be via anion exchange. The leaching was in good agreement with literature values, showed a positive correlation with extraction efficacies, and ranged for all extractions between 0.8 and 1.2%. Remarkably, increasing the temperature from 20 °C to 30 °C had no significant influence on leaching. Competing Interests: The authors declare no conflict of interest. (This journal is © The Royal Society of Chemistry.)
Databáze:	MEDLINE
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