Hydrophilic Modification And Antifouling Properties Of Polysulfone Ultrafiltration Membrane

The polysulfone membranes are easily fouled in the use process due to strong hydrophobic property,which can result in a massive decline in permeability and life span of the membrane.In addition,one of the problems of polymer membranes such as polysulfone membrane is the restrictive relation between flux and retention rate.Many modified methods result in a decrease in rejection rate of with increasing water flux,and a decrease in water flux with raising the rejection rate.Therefore,it is necessary to improve the antifouling performance and permeability of the membrane simultaneously.This study has designed and prepared the amphiphilic block copolymers PDMS-b-mPEG as additives to modify polysulfone membrane,achieving high water flux and excellent antifouling polysulfone membrane.In this paper,a series of different proportion of hydrophilic/hydrophobic amphiphilic block copolymer PDMS-b-mPEG containing hydrophilic mPEG and low surface energy PDMS was synthesized by simple and efficient Steglich esterification.The successful synthesis of PDMS-b-mPEG was confirmed by ~1H NMR and GPC.The copolymers as additives was blened with polysulfone to fabricate modified membrane(PSf/PDMS-b-mPEG)through non-solvent induced phase separation(NIPS).The SEM images show that the distribution of fingerlike macroporous and Spongelike macroporous can be controlled by controlling the ratio of the hydrophilic/hydrophobic components of the additives.The distribution of additives and wettability on the modified membrane surface can be confirmed by X-ray photoelectron spectroscopy(XPS),Energy Dispersive X-Ray Spectroscopy(EDX)and contact angle test.The permeability and antifouling properties of the modified membrane were evaluated by ultrafiltration experiment of pure water and bovine serum albumin(BSA)buffer.Compared with the pristine membrane,the permeability and antifouling properties of the modified membrane,especially for membrane PSf/PDMS-b-mPEG1900(P3),was effectively improved.The water flux of membrane P3(239.4 L/m~2h·bar)was 12 times higher than that of the pristine membrane P0(18.9L/m~2h·bar).It is important that the flux recovery rate of the membrane P3 is up to 89.2%and the flux reduction rate is as low as 10.8%at the rejection rate of about 80%.The results show that the polysulfone membrane blended with PDMS-b-mPEG have excellent antifouling performance and permeability.