Antifouling capability of polyvinylidene fluoride ultrafiltration membranes prepared with poly sulfobetaine methacrylate-modified graphene oxide

To mitigate the decrease in the separation efficiency caused by membrane fouling during the operation of polyvinylidene fluoride (PVDF) ultrafiltration membrane, this experiment employed methylacrylic sulfobetaine (SBMA)-modified graphene oxide (GO) nanoparticles improve the antifouling capability of ultrafiltration membrane. In this study, the hydrophilic material SBMA was grafted onto the surface of GO by free radical polymerization to form PSBMA@GO hydrophilic nanoparticles. PVDF ultrafiltration membranes containing GO nanoparticles or PSBMA@GO nanoparticles were prepared by the phase inversion method for comparative testing. The experimental results showed that after the addition of 0.75 wt% PSBMA@GO nanoparticles, the pure water flux of the PVDF ultrafiltration membrane and the hydrophilicity of the surface were the highest. Based on the scanning electron microscopy (SEM) and atomic force microscopy (AFM) results, the pore structure of the cross section was optimal and the surface roughness was the lowest. Based on the results from the cyclic filtration tests of three typical foulants, the PVDF ultrafiltration membrane with 0.75 wt% PSBMA@GO nanoparticles had the best antifouling capability. Furthermore, the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory was used to explore the interaction energy between foulants and the membrane when in close contact. The results showed that compared to the addition of the GO nanoparticles, the PVDF ultrafiltration membrane with the addition of the PSBMA@GO nanoparticles exhibited a lower attractive interaction energy with foulants. Therefore, the addition of the hydrophilic nanoparticles modified by the hydrophilic material SBMA to ultrafiltration membranes provides a potential new method to improve the antifouling capability of these materials in the future.