A microfluidic study of synergic liquid–liquid extraction of rare earth elements

A microfluidic technique is associated to X-ray fluorescence in order to investigate the origin of the so-called synergy effect observed in liquid-liquid extraction of rare earth elements (REE) when special combinations of two extractants – one solvating and one ionic- are used.The setup enables kin...

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Main Authors: El Maangar, Asmae, Theisen, Johannes, Penisson, Christophe, Zemb, Thomas, Gabriel, Jean-Christophe P.
Other Authors: Energy Research Institute @ NTU (ERI@N)
Format: Journal Article
Language:English
Published: 2020
Subjects:
Online Access:https://hdl.handle.net/10356/142535
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author El Maangar, Asmae
Theisen, Johannes
Penisson, Christophe
Zemb, Thomas
Gabriel, Jean-Christophe P.
author2 Energy Research Institute @ NTU (ERI@N)
author_facet Energy Research Institute @ NTU (ERI@N)
El Maangar, Asmae
Theisen, Johannes
Penisson, Christophe
Zemb, Thomas
Gabriel, Jean-Christophe P.
author_sort El Maangar, Asmae
collection NTU
description A microfluidic technique is associated to X-ray fluorescence in order to investigate the origin of the so-called synergy effect observed in liquid-liquid extraction of rare earth elements (REE) when special combinations of two extractants – one solvating and one ionic- are used.The setup enables kinetic studies by varying the two phases’ contact time. Results obtained are compared to those obtained using standard batch extraction method with equal contact time. We then determine variation of free energies of transfer for five rare earth elements present in solution together with a non-target ion (Fe3+) at different pH. Analysis of the effect of temperature, as well as of surface charge density of the coexisting cations, allow separating electrostatic from complexation effects. We finally show that all non-linear (synergic) effects are quadratic in mole fraction. This demonstrates that in-plane mixing entropy of the bent extractant film, in the first nanometer around rare earth ions, is the determining term in the synergy effect. Surprisingly, even when the third phase is present, free energies of transfer could still be measured in the diluted phase, which is reported for the first time, to our knowledge. We hence show that the extractive power of the dense third phase is stronger than conventional reverse aggregates in equilibrium with excess water.
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spelling ntu-10356/1425352021-01-08T01:31:53Z A microfluidic study of synergic liquid–liquid extraction of rare earth elements El Maangar, Asmae Theisen, Johannes Penisson, Christophe Zemb, Thomas Gabriel, Jean-Christophe P. Energy Research Institute @ NTU (ERI@N) Science::Chemistry Microfluidics Liquid-liquid Extraction A microfluidic technique is associated to X-ray fluorescence in order to investigate the origin of the so-called synergy effect observed in liquid-liquid extraction of rare earth elements (REE) when special combinations of two extractants – one solvating and one ionic- are used.The setup enables kinetic studies by varying the two phases’ contact time. Results obtained are compared to those obtained using standard batch extraction method with equal contact time. We then determine variation of free energies of transfer for five rare earth elements present in solution together with a non-target ion (Fe3+) at different pH. Analysis of the effect of temperature, as well as of surface charge density of the coexisting cations, allow separating electrostatic from complexation effects. We finally show that all non-linear (synergic) effects are quadratic in mole fraction. This demonstrates that in-plane mixing entropy of the bent extractant film, in the first nanometer around rare earth ions, is the determining term in the synergy effect. Surprisingly, even when the third phase is present, free energies of transfer could still be measured in the diluted phase, which is reported for the first time, to our knowledge. We hence show that the extractive power of the dense third phase is stronger than conventional reverse aggregates in equilibrium with excess water. NRF (Natl Research Foundation, S’pore) Published version 2020-06-24T01:43:42Z 2020-06-24T01:43:42Z 2020 Journal Article El Maangar, A., Theisen, J., Penisson, C., Zemb, T., & Gabriel, J.-C. P. (2020). A microfluidic study of synergic liquid–liquid extraction of rare earth elements. Physical Chemistry Chemical Physics, 22(10), 5449-5462. doi:10.1039/C9CP06569E 1463-9076 https://hdl.handle.net/10356/142535 10.1039/C9CP06569E 10 22 5449 5462 en SCARCE, USS-IF-2018-4 REE-CYCLE, ERC Grant Agreement N◦ [320915] Physical Chemistry Chemical Physics © 2020 The Owner Societies. This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. application/pdf
spellingShingle Science::Chemistry
Microfluidics
Liquid-liquid Extraction
El Maangar, Asmae
Theisen, Johannes
Penisson, Christophe
Zemb, Thomas
Gabriel, Jean-Christophe P.
A microfluidic study of synergic liquid–liquid extraction of rare earth elements
title A microfluidic study of synergic liquid–liquid extraction of rare earth elements
title_full A microfluidic study of synergic liquid–liquid extraction of rare earth elements
title_fullStr A microfluidic study of synergic liquid–liquid extraction of rare earth elements
title_full_unstemmed A microfluidic study of synergic liquid–liquid extraction of rare earth elements
title_short A microfluidic study of synergic liquid–liquid extraction of rare earth elements
title_sort microfluidic study of synergic liquid liquid extraction of rare earth elements
topic Science::Chemistry
Microfluidics
Liquid-liquid Extraction
url https://hdl.handle.net/10356/142535
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