Preparation of composite nanofiltration membranes with positive charges by surface grafting method and their Mg-Li separation properties
PA nanofiltration membrane was prepared by interfacial polymerization of piperazine(PIP)and homotrimethylene tricarbonyl chloride(TMC)as the base membrane.PEI-GOS nanofiltration membrane was prepared by surface grafting using a mixture of polyethyleneimine(PEI)and graphene oxide(GO)solution.The nanofiltration membranes were characterized by scanning electron microscope,Zeta potential analyzer and contact angle meter for micro-morphology,surface charge and water contact angle,etc.The magnesium-lithium separation performance of the nanofiltration membranes was investigated under the conditions of total solution mass concentration of 1 000 mg/L and Mg2+/Li+of 50.The results showed that the PEI-GOS nanofiltration membrane has a dense and smooth polyamide layer,the membrane surface is positively charged,the pure water flux can reach 50.1 L/(m2·h·MPa),and it has good retention performance for Mg2+.The magnesium-lithium separation factor of PEI-GOS nanofiltration membrane can reach 38.1,which is a good magnesium-lithium separation performance.
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维普
