Separation of Co(II) and Ni(II) Using an Analog of Glycine-Betaine Based on Task-Specific Ionic Liquids

A series of salts based on ethyl ester glycine-betaine derivatives, viz tri(<i>n</i>-pentyl)[2-ethoxy-2-oxoethyl]ammonium bromide, have been synthesized. These cations generate hydrophobic ionic liquids (ILs) with bis(trifluoromethylsulfonyl)imide (Tf<sub>2</sub>N<sup>−...

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Main Authors: Lamia Boulafrouh, Stéphanie Boudesocque, Aminou Mohamadou, Laurent Dupont
Format: Article
Language:English
Published: MDPI AG 2023-05-01
Series:Separations
Subjects:
Online Access:https://www.mdpi.com/2297-8739/10/5/305
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author Lamia Boulafrouh
Stéphanie Boudesocque
Aminou Mohamadou
Laurent Dupont
author_facet Lamia Boulafrouh
Stéphanie Boudesocque
Aminou Mohamadou
Laurent Dupont
author_sort Lamia Boulafrouh
collection DOAJ
description A series of salts based on ethyl ester glycine-betaine derivatives, viz tri(<i>n</i>-pentyl)[2-ethoxy-2-oxoethyl]ammonium bromide, have been synthesized. These cations generate hydrophobic ionic liquids (ILs) with bis(trifluoromethylsulfonyl)imide (Tf<sub>2</sub>N<sup>−</sup>) or dicyanamide (Dca<sup>−</sup>) anions. These new analogues of glycine-betaine-based ionic liquids (AGB-ILs) were characterized using spectroscopic methods (IR, <sup>1</sup>H, and <sup>13</sup>C NMR) and elemental analysis. These AGB-ILs were used for the selective separation of Ni(II) and Co(II) in saline media using pure ILs phase or ILs diluted in organic solvent. Interestingly, extraction of Co(II) and Ni(II) in Dca-based AGB-ILs can be enhanced using salts with chaotropic anions such as NaNO<sub>3</sub> (E > 90% for Co(II) and E = 85% for Ni(II)). Tf<sub>2</sub>N<sup>−</sup>-based ionic liquids do not extract Ni(II) or Co(II) even in NaCl 4M. Dca<sup>−</sup>-based ILs lead to a quasi-quantitative extraction of Co(II), while extraction of Ni(II) is limited to a few percent (17%) leading to separation factors higher than 100, ensuring a good separation of both metals. Cobalt could be back-extracted from the ionic liquid phase with water or with an aqueous solution of Na<sub>2</sub>SO<sub>4</sub>, which limits the release of the AGB cation in aqueous media, thus preserving its integrity. Results obtained by AGB-ILs diluted in organic solvent were comparable to those obtained with the pure AGB-ILs phase, indicating that this strategy can be deployed on systems working continuously out of equilibrium since the extraction mechanisms involve fast equilibria.
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spelling doaj.art-719a7d15fa774968880ac505d4e7da7e2023-11-18T03:16:13ZengMDPI AGSeparations2297-87392023-05-0110530510.3390/separations10050305Separation of Co(II) and Ni(II) Using an Analog of Glycine-Betaine Based on Task-Specific Ionic LiquidsLamia Boulafrouh0Stéphanie Boudesocque1Aminou Mohamadou2Laurent Dupont3Institut de Chimie Moléculaire de Reims (ICMR), Université de Reims Champagne-Ardenne, CNRS UMR 7312, UFR des Sciences Exactes et Naturelles, Bâtiment 18 Europol’Agro, BP 1039, CEDEX 2, F-51687 Reims, FranceInstitut de Chimie Moléculaire de Reims (ICMR), Université de Reims Champagne-Ardenne, CNRS UMR 7312, UFR des Sciences Exactes et Naturelles, Bâtiment 18 Europol’Agro, BP 1039, CEDEX 2, F-51687 Reims, FranceInstitut de Chimie Moléculaire de Reims (ICMR), Université de Reims Champagne-Ardenne, CNRS UMR 7312, UFR des Sciences Exactes et Naturelles, Bâtiment 18 Europol’Agro, BP 1039, CEDEX 2, F-51687 Reims, FranceInstitut de Chimie Moléculaire de Reims (ICMR), Université de Reims Champagne-Ardenne, CNRS UMR 7312, UFR des Sciences Exactes et Naturelles, Bâtiment 18 Europol’Agro, BP 1039, CEDEX 2, F-51687 Reims, FranceA series of salts based on ethyl ester glycine-betaine derivatives, viz tri(<i>n</i>-pentyl)[2-ethoxy-2-oxoethyl]ammonium bromide, have been synthesized. These cations generate hydrophobic ionic liquids (ILs) with bis(trifluoromethylsulfonyl)imide (Tf<sub>2</sub>N<sup>−</sup>) or dicyanamide (Dca<sup>−</sup>) anions. These new analogues of glycine-betaine-based ionic liquids (AGB-ILs) were characterized using spectroscopic methods (IR, <sup>1</sup>H, and <sup>13</sup>C NMR) and elemental analysis. These AGB-ILs were used for the selective separation of Ni(II) and Co(II) in saline media using pure ILs phase or ILs diluted in organic solvent. Interestingly, extraction of Co(II) and Ni(II) in Dca-based AGB-ILs can be enhanced using salts with chaotropic anions such as NaNO<sub>3</sub> (E > 90% for Co(II) and E = 85% for Ni(II)). Tf<sub>2</sub>N<sup>−</sup>-based ionic liquids do not extract Ni(II) or Co(II) even in NaCl 4M. Dca<sup>−</sup>-based ILs lead to a quasi-quantitative extraction of Co(II), while extraction of Ni(II) is limited to a few percent (17%) leading to separation factors higher than 100, ensuring a good separation of both metals. Cobalt could be back-extracted from the ionic liquid phase with water or with an aqueous solution of Na<sub>2</sub>SO<sub>4</sub>, which limits the release of the AGB cation in aqueous media, thus preserving its integrity. Results obtained by AGB-ILs diluted in organic solvent were comparable to those obtained with the pure AGB-ILs phase, indicating that this strategy can be deployed on systems working continuously out of equilibrium since the extraction mechanisms involve fast equilibria.https://www.mdpi.com/2297-8739/10/5/305cobaltnickeltask specific ionic liquid
spellingShingle Lamia Boulafrouh
Stéphanie Boudesocque
Aminou Mohamadou
Laurent Dupont
Separation of Co(II) and Ni(II) Using an Analog of Glycine-Betaine Based on Task-Specific Ionic Liquids
Separations
cobalt
nickel
task specific ionic liquid
title Separation of Co(II) and Ni(II) Using an Analog of Glycine-Betaine Based on Task-Specific Ionic Liquids
title_full Separation of Co(II) and Ni(II) Using an Analog of Glycine-Betaine Based on Task-Specific Ionic Liquids
title_fullStr Separation of Co(II) and Ni(II) Using an Analog of Glycine-Betaine Based on Task-Specific Ionic Liquids
title_full_unstemmed Separation of Co(II) and Ni(II) Using an Analog of Glycine-Betaine Based on Task-Specific Ionic Liquids
title_short Separation of Co(II) and Ni(II) Using an Analog of Glycine-Betaine Based on Task-Specific Ionic Liquids
title_sort separation of co ii and ni ii using an analog of glycine betaine based on task specific ionic liquids
topic cobalt
nickel
task specific ionic liquid
url https://www.mdpi.com/2297-8739/10/5/305
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AT stephanieboudesocque separationofcoiiandniiiusingananalogofglycinebetainebasedontaskspecificionicliquids
AT aminoumohamadou separationofcoiiandniiiusingananalogofglycinebetainebasedontaskspecificionicliquids
AT laurentdupont separationofcoiiandniiiusingananalogofglycinebetainebasedontaskspecificionicliquids