Facile sol-gel coating process for anti-biofouling modification of poly (vinylidene fluoride) microfiltration membrane based on novel zwitterionic organosilica

Present study proposed a novel strategy for membrane anti-biofouling modification based on facile sol-gel coating process and antifouling zwitterions. To this end, a novel zwitterionic organosilica monomer (zBPGH) was synthetized. Based on this, membrane was modified with zwitterionic organosilica through sol-gel coating process for conferring the surface anti-biofouling property, namely PVDF-c-pzBPGH. Then the surface physical and chemical properties were investigated by attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The results demonstrated that uniform and smooth organosilica xerogel coating was formed on membrane surface and the zwitterions were successfully introduced onto the membrane surface via coating. The water contact angle and hydration capacity measurements indicated that the zwitterions endowed PVDF-c-pzBPGH surface excellent hydrophilicity. Results of three-cycle filtration test revealed that PVDF-c-pzBPGH exhibited excellent and long-term antifouling ability to protein and polysaccharide with flux recovery rates of 67.76% and 90.66% respectively after three cycles of fouling. Moreover, the bacterial attachment test showed that PVDF-c-pzBPGH also possessed outstanding anti-bioadhesion ability. Such excellent anti-biofouling ability was mainly attributed to its zwitterionic surface; meanwhile the smoothing effect of coating can also play a role. Overall, this study provided a facile approach for improving the anti-biofouling ability of membrane.