Study on the surface functionalization of PVDF hollow-fiber membrane with polydopamine and poly(ethylene glycol)(PEG)

Polydopamine(PDOPA)deposition was used in this study to improve the surface hydrophilicity of the PVDF hollow-fiber membrane.In further,mPEG-NH2was grafted on the PDOPA layer through the adhesion of PDOPA to functionalize the membrane surface.The effects of PDOPA deposition and PEG grafting were compared under various reaction condition,and the separation efficiency of oil/water emulsion was used to evaluate the performance of modified membranes.The results showed that the PDOPA modified PVDF hollow-fiber membrane increased in hydrophilicity after 480minutes of dopamine deposition,the contact angle reduced from 84.9°to 50.1°,and the water penetration rate into membrane increased.Deposition time of PDOPA affected the pure water flux,with flux increasing 6.4% after30minutes of deposition.A lower decreasing rate of flux,a higher steady-state flux and a more excellent anti-fouling were observed for modified membranes during filtration of an oil/water emulsion.The PDOPA modified membranes got a further improvement in hydrophilicity after grafting mPEG-NH2,and the rejection of oil/water emulsion increased 13%.The results show that both the PDOPA modification and mPEG-NH2grafting improve the PVDF hollow-fiber membrane performance in the treatment of oil/water filtration effectively.