聚醚酰亚胺耐溶剂超滤膜的制备及性能研究

Preparation and properties of polyether imide solvent-resistant ultrafiltration membrane

采用浸没沉淀相转化法制备聚醚酰亚胺(PEI)平板超滤膜,考察了铸膜液中聚合物PEI浓度、添加剂聚乙烯吡咯烷酮(PVP)浓度对膜结构和性能的影响。为提高超滤膜的耐溶剂性能,采用己二胺(HDA)进行化学交联,并研究了不同交联时间下膜性能的差异。结果表明:在不降低膜分离性能的情况下,交联后的膜渗透通量得到了有效提高,在0.1 MPa运行压力下纯水通量由667.1 L/(m^(2)·h)提高到1126.1 L/(m^(2)·h),而对1.0 g/L牛血清白蛋白(BSA)溶液的截留率保持在97%以上。膜溶剂吸附实验发现,在6种不同溶剂中浸泡48 h后,未交联膜在N,N-二甲基甲酰胺(DMF)中已完全溶解,而交联膜仍保持着良好的膜形态,吸附量为0.86 g/g,在乙醇、异丙醇、正己烷、1 mol/L HCl溶液中的吸附量均小于未交联膜,在1 mol/L NaOH溶液中反而增加,说明制备得到的交联膜具有良好的耐溶剂性能和耐强酸性能,耐强碱性能反而变差。

Polyether imide(PEI)flat ultrafiltration membrane was prepared by immersion precipitation phase inversion method.The effects of polymer PEI concentration and additive polyvinylpyrrolidone(PVP)concentration on the structure and properties of membrane were investigated.In order to improve the solvent resistance of ultrafiltration membrane,hexamethylenediamine(HDA)was used for chemical crosslinking,and the difference of membrane performance under different crosslinking time was studied.The results show that the flux of the crosslinked membrane is effectively improved without reducing the membrane separation performance compared with the uncrosslinked ultrafiltration membrane.Under the operating pressure of 0.1 MPa,the flux of pure water is increased from 667.1 L/(m^(2)·h)to 1126.1 L/(m^(2)·h),while the rejection rate of 1.0 g/L BSA solution remains above 97%.After soaking in six different solvents for 48 h,it was found that the uncrosslinked membrane is completely dissolved in N,N-dimethylformamide(DMF),while the crosslinked membrane still maintains a good membrane morphology with an adsorption capacity of 0.86 g/g.The adsorption capacity in ethanol,isopropanol,n-hexane and 1 mol/L HCl solution is smaller than that of the uncrosslinked membrane,but is increased in 1 mol/L NaOH solution,which indicates that the prepared crosslinked membrane has good solvent resistance and strong acid resistance,but the strong alkali resistance becomes worse.