Cyanex923/TBP/PHEN协同2-噻吩甲酰三氟丙酮对Li(Ⅰ)的电膜萃取研究  

Electro-membrane extraction of Li(Ⅰ)by Cyanex923/TBP/PHEN in collaboration with 2-thiophenecarbonyltrifluoroacetone

作　　者：孟晓荣[1] 孙驰 龙伊文 MENG Xiaorong;SUN Chi;LONG Yiwen(School of Chemistry and Chemical Engineering,Xi'an University of Architecture and Technology,Xi'an 710055,Shaanxi,China;Xi'an Runqin Water Limited Liability Company,Xi'an 710048,Shaanxi,China)

机构地区：[1]西安建筑科技大学化学与化工学院,陕西西安710055 [2]西安润秦水务有限责任公司,陕西西安710048

出　　处：《化工学报》2024年第12期4606-4616,共11页CIESC Journal

基　　金：国家重点研发计划项目(2022YFC2904304-01);陕西省技术创新引导专项-重点研发计划三项改革项目(2023GXLH-060)。

摘　　要：为强化2-噻吩甲酰三氟丙酮(HTTA)萃锂体系的性能,分别制备了以三烷基氧化膦、磷酸三丁酯、邻菲罗啉3种协萃剂配伍的聚氯乙烯基二元复合萃取膜(PT-PIMs),用于研究电场强化的膜萃取提锂技术。考察了膜相组成和操作电压对Li(Ⅰ)传质性能的影响规律,结合表面红外和扫描电镜对PT-PIMs的表征结果,初步探索了PTC-PIM-Li(Ⅰ)电膜萃取机制。研究表明:在PT-PIMs体系中,HTTA通过烯醇化结构与Li(Ⅰ)形成离子型配合物,在PT-PIMs中起主萃作用。3种协萃剂通过对HTTA的去质子化协同传质,并因协萃剂的碱性及塑化能力的不同而导致3种PT-PIMs对Li(Ⅰ)的传质能力不同。Li(Ⅰ)在膜界面的传质机制为“离子交换-中和”,外加电场通过强化TTA-Li(Ⅰ)配合物解离而促进传质,但同时会受限于PT-PIMs膜界面的化学反应速率。经煤油改性后的PT-PIMs-Li(Ⅰ)体系在四次循环后Li(Ⅰ)的渗透速率下降率<21%;在料液相Li(Ⅰ)∶Na(Ⅰ)∶K(Ⅰ)质量浓度比为20∶20∶20时,PT-PIMs体系分离因子SLi(Ⅰ)/Na(Ⅰ)和SLi(Ⅰ)/K(Ⅰ)分别为8.41、4.88、3.88和7.99、4.64、3.81,显示了Li选择性分离能力。Lithium resource plays an important role in energy strategy.Membrane extraction technology is expected to solve the green sustainability problem of liquid lithium resource extraction.Binary composite extraction membranes PT-PIMs(PTC-PIM/PTT-PIM/PTP-PIM)with 2-thiophenoyltrifluoroacetone(TTA)synergistically solvated carriers[trialkylphosphine oxide mixture(Cyanex923)/tributyl phosphate(TBP)/phenanthroline(PHEN)]were prepared.The mass transfer behaviour of PT-PIMs-Li(Ⅰ)system by electric field enhancement was investigated under optimized membrane phase conditions,and the stability and Li/Na/K selective separation performance of the kerosene-modified PK-PIMs-Li(Ⅰ)system were evaluated.The results show that the membrane phase composition has a large effect on the mass transfer rate of Li(Ⅰ),the main extractant TTA plays a dominant role in Li(Ⅰ)mass transfer,and the mass transfer rate increases with the voltage.The permeability coefficient of PTC-PIM-Li(Ⅰ)system increases linearly with increasing voltage.The permeability coefficient of PTC-PIM-Li(Ⅰ)system is 33.20μm·s-1 at 40 V.The permeation rate of Li(Ⅰ)in the PT-PIMs-Li(Ⅰ)system modified by kerosene decreased by<21%after four cycles;When the mass concentration ratio of Li(Ⅰ)∶Na(Ⅰ)∶K(Ⅰ)in liquid phase is 20∶20∶20,the separation factors SLi(Ⅰ)/Na(Ⅰ)and SLi(Ⅰ)/K(Ⅰ)of PT-PIMs system are 8.41,4.88,3.88 and 7.99,4.64,3.81,respectively,indicating the selective separation ability of Li.The combined permeability coefficient,stability and PK-PIMs-Li(Ⅰ)systems:PCK-PIM>PTK-PIM>PPK-PIM.This paper provides an important idea for sustainable extraction technology of lithium resources with green energy saving.

关 键 词：锂 膜 电膜萃取 HTTA+协萃剂 稳定性 选择性 

分 类 号：TQ317.4[化学工程—高聚物工业]