Preparation of Electro-nanofiltration Membranes with High Li+/Mg2+Separation Performance via Sequential Interfacial Polymerization
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 regula-tion 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 foun-dation for the subsequent research and application of Li+/Mg2+separation salt-lake brines.
国家科技期刊平台
NSTL
万方数据
