Role of ionic liquids in the efficient transfer of lithium by Cyanex 923 in solvent extraction system

Abstract

The solvent extraction of Li + by Cyanex 923 was investigated upon the addition of different imidazolium-based ionic liquids (ILs). The results showed 1-hydroxylethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([HOEmim][NTf 2 ]) can improve the extraction of Li + most effectively. The fundamental mechanism is that [HOEmim] [NTf 2 ] can remarkably enhance the coordination ability of Cyanex 923 to Li + to form more stable and hydrophobic ion-pair species [Li(Cyanex 923) n ][NTf 2 ] (n max = 3) resulting from the electrostatic interaction and typical hydrogen bonding of IL, and thus facilitating the transfer of Li + into organic phase. This work has revealed the transfer mechanism of Li + in a solvent extraction system comprising of IL and neural ligand. The knowledge of the coordination environment of Li + in the presence of IL also gives us a new insight into the separation of 6 Li/ 7 Li. The disadvantage of this process is the loss of IL. However, this study provides guidance for the design of better IL-based systems for the separation of metal ions. K E Y W O R D S extraction, ionic liquids, lithium, trialkylphosphine oxide 1 | INTRODUCTION Lithium (Li) is a strategic metal. It has a wide variety of applications in the area of nuclear energy, 1 aeronautics and astronautics, lithium batteries, 2 glasses, and ceramics. With the growing market in electronics and new

Efficient Extraction of Lithium Ions from High Mg/Li Ratio Brine through the Synergy of TBP and Hydroxyl Functional Ionic Liquids

“…The ESI‐MS spectra and slope methods yet were employed to determine the quantity relationship between the extracted ions and TBP. [ 36,39 ] To further analyze the composite of lithium and magnesium complexes with TBP which were formed in the extraction process, ESI‐MS spectrum of the loaded organic phase was characterized, and the results are shown in Figure 8. The peak at 289.1489 was [Na·TBP] + , which was the peak of the free TBP in the organic phase.…”

“…1‐(2‐Hydroxyethyl)‐3‐methylimidazolium bis(trifluoromethyl sulfonyl)imide ([HOEmim][NTf 2 ]), as co‐extractant, was reported in our previous work [ 36,37 ] that exhibited excellent performance in separating Li + from the alkali aqueous solution with high sodium to lithium ratio. In this work, [HOEmim][NTf 2 ] was chosen to separate Li + from the brine with high Mg/Li mass ratio with TBP, and a possible recycle route of IL‐based extraction system was put forward.…”

A simple model for precisely describing liquid–liquid equilibrium and better understanding extraction mechanism

“…Liquid–liquid extraction is a widely used separation technology in many fields of chemical industry, for example, removal of aromatic sulfurs and nitrogens from fuel oil, 1‐9 separation of phenols or cresols from coal tar oil or water, 10‐15 recovery of organic acids and metal ions from aqueous solution, 16‐20 and so forth. Between two solvent phases (α and β), the distribution of solute (A) equilibrium concentrations ( C A ) is crucial for liquid–liquid equilibrium (LLE) systems 21,22 .…”

Selective removal of magnesium from lithium‐rich brine for lithium purification by synergic solvent extraction using β‐diketones and Cyanex 923

“…7 Li NMR spectrum is a useful probe to study the speciation of Li in solvent extraction 40 . 7 Li NMR spectra were recorded for the organic phase loaded with Li (Figure 9a).…”