表面接枝法荷正电复合纳滤膜制备及其镁锂分离性能

Preparation of composite nanofiltration membranes with positive charges by surface grafting method and their Mg-Li separation properties

以哌嗪(PIP)与均苯三甲酰氯(TMC)界面聚合制备的PA纳滤膜为底膜,利用聚乙烯亚胺(PEI)与氧化石墨烯(GO)混合溶液对膜表面进行接枝,并制备PEI-GOS纳滤膜.通过扫描电镜(SEM)、Zeta电位和接触角等仪器对其微观形貌、表面电荷和水接触角等进行表征.在溶液总质量浓度1000 mg/L(镁锂质量浓度比为50)的条件下,考察了纳滤膜的镁锂分离性能.结果表明,PEI-GOS纳滤膜具有致密平滑的聚酰胺层,膜表面荷正电,纯水通量可达50.1 L/(m^(2)·h·MPa),对Mg^(2+)具有良好的截留性能.PEI-GOS纳滤膜镁锂分离因子可达38.1,具备良好的镁锂分离性能.

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 1000 mg/L and Mg^(2+)/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/(m^(2)·h·MPa),and it has good retention performance for Mg^(2+).The magnesium-lithium separation factor of PEI-GOS nanofiltration membrane can reach 38.1,which is a good magnesium-lithium separation performance.