离子液体/苯并15-冠-5浸渍XAD-7树脂萃取分离锂同位素  

Extraction Separation of Lithium Isotopes by Using XAD-7 Resins Impregnated With Ionic Liquid and Benzo-15-Crown-5

作　　者：顾玲 孙晓利 任冬红 邱丹 顾志国 李在均 

机构地区：[1]江南大学化学与材料工程学院,江苏无锡214122

出　　处：《核化学与放射化学》2015年第6期415-424,共10页Journal of Nuclear and Radiochemistry

基　　金：国家自然科学基金资助项目(21101078;21276105);新世纪优秀人才计划资助项目(NCET-11-0657)

摘　　要：以XAD-7树脂为支撑担体制备了含有三种不同咪唑型离子液体（[C_8mim][BF_4]、[C_8mim][PF_6]、[C_8mim][（SO_2CF_3）_2N]）和萃取剂（苯并15-冠-5）的浸渍树脂,并用于锂同位素的萃取分离。浸渍树脂的红外和扫描电镜表征表明,离子液体成功负载到了树脂上;热重分析表明,该浸渍树脂具有良好的热稳定性。在水相初始pH=5.55时,浸渍树脂具有最佳萃取率。浸渍树脂在LiSCN溶液中具有较高的萃取率,而在CF_3COOLi溶液中呈现较大的单级分离因子,最大单级分离因子达到1.045±0.002。浸渍树脂的萃取平衡时间为2.5～3h。萃取热力学研究表明,该反应为自发过程,温度对体系的影响较小。~6Li富集于固相,~7Li富集在水相。该系列浸渍树脂易于再生,可循环使用。Imidazolium-type ionic liquid （[C8mim] [BF4], [C8mim] [PF6] and [C8mim] [（SO2CFs）2N]） and benzo-15-crown-5 were immobilized on XAD-7 resin to obtain the im- pregnated resin for lithium isotopes separation. IR and SEM characterizations of the impreg- nated resins indicate that ionic liquids and benzo-15-crown-5 are immobilized in the resins successfully and the thermal analysis indicates that the materials are thermally stable. The optimum E was obtained in the initial solution at pH：5.55. The larger extraction percenta- ges and separation factors values were obtained from LiSCN solution and CFsCOOLi solu- tion, respectively. The maximum single-stage isotopes separation factor of 6Li/7Li is up to 1. 045±0. 002. The equilibrium time of extraction is attained in 2.5-3 h. The thermodynamic parameters of the system were presented and revealed that the extraction reaction was aspontaneous process and the temperature had slight influence on the extraction separation of lithium isotopes. The mechanism of extraction system show that 6Li enriches in the solid phase and 7Li concentrates in the aqueous phase. The impregnated resins can be regenerated and reused for lithium isotopes separation.

关 键 词：锂同位素分离 萃取 离子液体 浸渍树脂 苯并15-冠-5 

分 类 号：O658.2[理学—分析化学]