Zwitterionic SiO2 nanoparticles as novel additives to improve the antifouling properties of PVDF membranes

Hybrid polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes with excellent antifouling properties were prepared by non-solvent-induced phase separation through blending zwitterionic SiO2 nanoparticles. Lysine was used to modify SiO2 nanoparticles to generate a surface zwitterion of the amino acid type. Zwitterionic SiO2 nanoparticles were distributed uniformly in the membrane bulk to avoid massive agglomeration and to significantly improve the hydrophilicity and separation performance of PVDF UF membranes. The amount of BSA adsorbed on a hybrid ZP-5% membrane surface of static fouling test decreased to 10 μg cm−2, and the secondary water flux recovery rate (FRR) increased to more than 95% for the dynamic antifouling test of BSA and HA. The addition of zwitterionic SiO2 nanoparticles enhanced the antifouling ability of the membrane through inhibiting irreversible fouling and prolonging the service life of the PVDF UF membrane.