Lithium isotope separation by liquid-liquid extraction using ionic liquid system containing dibenzo-14-crown-4

• Published in: Journal of molecular liquids Vol. 224; pp. 662 - 667
• Main Authors: Shi, Chenglong, Jia, Yongzhong, Xiao, Jiang, Wang, Xingquan, Yao, Ying, Jing, Yan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2016
• Subjects: Dibenzo-14-crown-4; Ionic liquids; Lithium isotopes; Solvent extraction; Ionic liquids; Lithium isotopes; Solvent extraction; Dibenzo-14-crown-4
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2016.10.081

In this paper, a novel liquid-liquid extraction system was investigated for the selective separation of lithium isotopes using ionic liquid (IL) and dichloroethane as extraction solvent and dibenzo-14-crown-4 (DB14C4) as extractant. Results showed that the separation performance of DB14C4 has been improved after the ILs were involved in the extraction process. The maximum single stage separation factor α for 6Li/7Li obtained in the present study was 1.021. The light lithium isotope 6Li and the heavy lithium isotope 7Li were concentrated in organic phase and solution phase, respectively. The order of the single stage separation factor obtained in different lithium salts was LiI>LiBr>LiClO4>LiCl. From the temperature dependence data, the thermodynamic functions values of the lithium isotope exchange reaction were calculated. The crown ether, dibenzo-14-crown-4(DB14C4), exhibited good selectivity and separation performance for lithium isotopes in ionic liquid systems. [Display omitted] •The dibenzo-14-crown-4 (DB14C4) was successfully synthesized and used for the lithium isotope separation.•Adding ionic liquid into the organic phase could improve the separation performance of DB14C4.•Nature of extracted species was found out to be 1:1.•Thermodynamics studies indicated spontaneous reactions.