Chem. J. Chinese Universities ›› 2024, Vol. 45 ›› Issue (6): 20230484.doi: 10.7503/cjcu20230484

• Polymer Chemistry • Previous Articles     Next Articles

Preparation of Electro-nanofiltration Membranes with High Li+/Mg2+ Separation Performance via Sequential Interfacial Polymerization

LIU Huili, WANG Jing(), CHEN Jiashuai, SONG Zhihao, JIANG Yumeng, GUO Zhiyuan, ZHANG Panpan, JI Zhiyong   

  1. Engineering Research Center of Seawater Utilization Technology of Ministry of Education,Hebei Collaborative Innovation Center of Modern Marine Chemical Technology,School of Chemical Engineering and Technology,Hebei University of Technology,Tianjin 300401,China
  • Received:2023-11-22 Online:2024-06-10 Published:2024-04-12
  • Contact: WANG Jing E-mail:wangjing1989@hebut.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(22108057);Hebei Province Key R&D Program, China(22108057)

Abstract:

Highly selective electro-nanofiltration membranes(ENFMs) were prepared by regulating the aqueous-phase monomers of interfacial polymerization(IP) and constructing the positively charged surface by sequential interfacial polymerization(SIP) for the separation of lithium and magnesium by selective electrodialysis processes. The IP reaction was carried out using different aqueous-phase monomers with trimesoyl chloride to achieve the regulation of the pore size and charging property of the separation membranes. The optimum Li+/Mg2+ separation performance(4.75) of the membrane was achieved when piperazine was used as the aqueous-phase monomer. Subsequently, the SIP reaction was utilized to introduce positively charged aqueous-phase monomer polyethyleneimine(PEI, MW=70000) of different concentrations on the optimal IP membrane surface, which converted the charge of the membrane surface from negative to positive. With the increase of PEI concentration, the positive charge density on the membrane surface increased significantly; the optimal SIP membrane achieved outstanding selectivity for Li+/Mg2+(15.90) and high Li+ flux(3.26×10‒8 mol⋅cm‒2⋅s‒1), which breaks the traditional “Trade-off” effect and lays the foundation for the subsequent research and application of Li+/Mg2+ separation salt-lake brines.

Key words: Interfacial polymerization, Electro-nanofiltration membrane, Selective electrodialysis, Li+/Mg2+ separation

CLC Number: 

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