The synergistic extraction of heavy rare earth elements using EHEHP-type and BTMPP-type functional ionic liquids

Abstract

Heavy rare earth elements (HREEs) are more important than light rare earth elements (LREEs) since the supply risk and application in clean energy. In this paper, we first reported the synergistic extraction based on 2-ethyl(hexyl) phosphate mono-2-ethylhexyl ester (EHEHP)-type and bis-(2,4,4-trimethylpentyl) phosphate (BTMPP)-type acid base coupling bifunctional ionic liquids (ABC-BILs) for HREEs separation. Extractabilities of the novel systems were better than those of mixed 2-ethyl(hexyl) phosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) and bis(2,4,4-trimethylpentyl) phosphinic acid (HBTMPP). Also, stripping property of the ABC-BIL based synergistic extraction system for HREE was better than that of mixed HEH[EHP] and HBTMPP. Advantages of the novel synergistic system based on ABC-BILs have revealed potential application values for HREEs separation industry.

Synergistic Effect of Doped Functionalized Ionic Liquids in Silica Hybrid Material for Rare Earth Adsorption

“…The anionic siloxy oxygen was also reported in some other papers. , When the sol–gel polymerization of TEOS proceeded in the organic gel state, the gelator strands acted as a template, which eventually created a void in the resultant silica . In our earlier study, the extraction mechanism of functionalized IL for REE was indicated to be ion association (i.e., the IL’s cation revealed obvious electrostatic interaction with the negative species formed by REE and IL’s anion). , On the basis of the investigations mentioned above, herein the porogen effects of [P 66614 ]­[EHEHP] and [N 1888 ]­[BTMPP] together with the electrostatic interactions between anionic silicate, ILs, and REE are concluded to be as Scheme .…”

Task-Specific Ionic Liquids as Extractants for the Solvent Extraction of Molybdenum(VI) from Aqueous Solution Using Different Commercial Ionic Liquids as Diluents

“…Several studies have proposed the extraction stoichiometry when ammonium-based ionic liquids were used as extractant in metal extraction processes. In those studies, a solvation mechanism was reported when the ionic liquids were diluted in molecular diluents. ,, However, the equilibrium pH of those works was around a value of 4. In this study, the initial pH was around a value of 0.5 to ensure the extraction of the MoO 2 2+ cation.…”

“…In those studies, a solvation mechanism was reported when the ionic liquids were diluted in molecular diluents. 32,35,38 However, the equilibrium pH of those works was around a value of 4. In this study, the initial pH was around a value of 0.5 to ensure the extraction of the MoO 2 2+ cation.…”

“…Normally, in these works, the anion of an ionic liquid is functionalized with a specific group to extract metal species. For instance, the ionic liquids tetrabutylammonium bis­(2-ethylhexyl)-phosphate, [N 4,4,4,4 ]­[D2EHP], and tetraoctylammonium bis­(2-ethylhexyl)-phosphate, [N 8,8,8,8 ]­[D2EHP], were used as the extractants to recover lithium; trihexyl­(tetradecyl)­phosphonium benzoate [P 6,6,6,14 ]­[BA] was used to extract rare earths; − and trihexyltetradecylphosphonium 2-(propylthio)­benzoate [P 6,6,6,14 ]­[PTB] and 2-(benzylthio)­benzoate [P 6,6,6,14 ]­[BTB] were reported to extract transition metals and diketanoate-anion-based ionic liquids for the extraction of Eu­(III) and Am­(III) . Most of these studies have used neat TSILs without a diluent, and a few others have used TSILs in combination with molecular diluents producing high values of extraction percentage.…”

Application of a functionalized ionic liquid extractant tributylmethylammonium dibutyldiglycolamate ([A336][BDGA]) in light rare earth extraction and separation

“…Alternatively, the extraction sequence of Ln(III) was also attributed to its ionic radius. This result can be related to the hydration energy of the Ln(III) ion during extraction [ 21 , 28 ].…”