PVP造孔添加剂对聚偏氟乙烯水处理分离膜性能的影响

Effect of PVP pore forming additive on the performance of polyvinylidene fluoride water treatment separation membrane

采用离子液体溴化1-丁基-3-乙烯基咪唑(ILs)为亲水改性剂,水溶性聚合物聚乙烯吡咯烷酮(PVP)为造孔添加剂,将辐照后的聚偏氟乙烯(PVDF)粉末溶于N,N-二甲基乙酰胺(DMAc)中,完全溶解后进行ILs原位聚合,应用相转换法制备PVDF-g-ILs水处理分离薄膜。通过改变铸膜液中PVP含量调控薄膜性能,研究发现,随着PVP含量的增加,PVDF-g-ILs膜孔径和孔隙率增大,通量升高。染料分离实验结果表明,孔径越大,对荷负电的污染物截留率越差。在分离过程中,PVDF-g-ILs膜能高效截留罗丹明6G的水溶液,但是对橙黄G染料的截留率较低,原因在于PVDF-g-ILs膜表现为正电性。

Ionic liquid 1-butyl-3-vinyl imidazole bromide(ILs)was used as hydrophilic modifier and water-soluble polymer polyvinylpyrrolidone(PVP)was used as pore forming additive.The irradiated polyvinylidene fluoride(PVDF)powder was dissolved in dimethylacetamide(DMAC),and then ILs was polymerized in situ.PVDF-g-ILs water treatment separation membrane was prepared by phase conversion method.The properties of PVDF-g-ILs films were controlled by changing the PVP content in the casting solution.It was found that with the increase of PVP content,the pore size and porosity of PVDF-g-ILs films increased,and the flux increased.The results of dye separation experiments showed that the larger the pore size induced the worse retention rate of charged pollutants.In the separation process,PVDF-g-ILs membranes efficiently intercepted the aqueous solution of Rhodamine 6G,but the rejection rate of orange G dye wass low because PVDF-g-ILs membrane was positively charged.