Lithium isotopes separation by using benzo-15-crown-5 in eco-friendly extraction system

• Published in: Journal of molecular liquids Vol. 241; pp. 946 - 951
• Main Authors: Xiao, Jiang, Jia, Yongzhong, Shi, Chenglong, Wang, Xingquan, Wang, Su, Yao, Ying, Jing, Yan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2017
• Subjects: Benzo-15-crown-5; Ionic liquid; Lithium isotopes; Separation; Solvent extraction; Lithium isotopes; Separation; Benzo-15-crown-5; Solvent extraction; Ionic liquid
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2017.06.119

A green and efficient liquid–liquid extraction system was developed for the separation of lithium isotopes by using hydrophobic ionic liquids (ILs=[C4,6,8,10mim]+[NTf2]−) as extraction organic phase and benzo-15-crown-5 (B15C5) as complexing agent. The maximum single-stage separation factor α of 6Li/7Li obtained in this study was 1.029±0.001, indicating 6Li was enriched in ionic liquid phase while 7Li was concentrated in the aqueous phase. The lithium ion was extracted into the ionic liquid in the formation of 1:2 complex [Li+(B15C5)2]. The negative data of thermodynamic parameters (∆H0 and ∆G0) suggest that the extraction system was a spontaneous exothermic process. In addition, effective lithium isotopes separation factor and the extraction efficiency of lithium ions can be gained in the condition of lower temperature with softer counter anions in the novel extraction system. [Display omitted] •A green and efficient water-ionic liquids extraction system was investigated for selective separation of lithium isotopes.•The maximum single-stage separation factor α of 6Li/7Li obtained in present study was 1.029±0.001.•The formation of 2:1 complex Li(B15C5)2+ in the organic phase was determined.•The extraction system has a promising application prospect in separating lithium isotope from LiCl solution.