The Properties Of Charged Membranes By Ultraviolet Irradiation Induced Graft Copolymerization

By ultraviolet(UV) irradiation induced graft polymerization, acrylic acid (AAc) and an epoxy-group-containing polymer chain, glycidyl methacrylate(GMA), were respectively grafted onto the porous polypropylene hollow fiber (PP) membrane. Applying FTIR-ATR spectroscopy, and Scan electron microscope(SEM) , analysis showed that the membrane of PP—g—AAc and PP—g—GMA were gained successfully, and ring opening of the PP—g—GMA epoxy group was induced in the presence of cysteine(Cys) including amido and carboxyl.The charged membrane has been studied by using the streaming potential method. Experiment indicate that charged membrane ,with varying of the pH, streaming potential changing. In the low pH , PP-g-AAc, PP-g-Cys have positive charged, and rising with the increasing of pressure. In high pH, the streaming potential of the membrane moved to the negative charged.Filtration performances on the bovine serum albumin(BSA) and membrane fouling were studied. In acidity condition , the filtration quantity of BSA is larger than in alkalescence condition. The results suggested the rate of filtrating BSA for PP—g —AAc and PP—g—Cys membrane were higher than for PP membrane.PP—g—AAc has negative charged, it must be avoided acidity condition when it apply to separate the protein. PP—g—Cys is amphoteric charged membrane, it can be applid in acidity condition and alkalescence condition apart from isoelectric points of BSA.