Novel polyethersulfone hybrid ultrafiltration membrane prepared with SiO2-g-(PDMAEMA-co-PDMAPS) and its antifouling performances in oil-in-water emulsion application

To avoid the agglomeration of nanoparticles (NPs) in hybrid membranes and alleviate the leakage of NPs during the oily wastewater treatment process, poly(2-(dimethylamino)ethylmethacrylate-co-3-dimethyl(methacryloyloxyethyl)ammoniumpropanesulfonate) (PDMAEMA-co-PDMAPS) grafted silica (SiO2) [SiO2-g-(PDMAEMA-co-PDMAPS)] NPs were prepared by grafting PDMAEMA brushes onto SiO2 NPs surface via the surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (Si-ARGET ATRP). Subsequently, the quaternization of the tertiary amine groups in PDMAEMA and 1,3-propanesultone was performed to get [SiO2-g-(PDMAEMA-co-PDMAPS)] NPs. Then, the organic-inorganic hybrid polyethersulfone (PES) membranes with different ratios of SiO2 NPs (m membranes) and SiO2-g-(PDMAEMA-co-PDMAPS) NPs (M membranes) were fabricated via the non-solvent induced phase separation (NIPS) process. Transmission electron microscopy (TEM) images demonstrated that the modification of SiO2 NPs with PDMAEMA-co-PDMAPS was favorable for their homogeneous dispersion in organic solvents. The results of scanning electron microscopy (SEM) images indicated that the surface porosity and mean pore size of hybrid membranes were increased compared to the neat PES membrane. Furthermore, the M membranes exhibited better hydrophilicity, pure water flux and oil flux than neat PES membrane and m membranes. It was found from filtration results that the total fouling (Rt) and irreversible fouling (Rir) were significantly reduced due to higher hydrophilicity of hybrid membranes. In addition, after oil-in-water emulsion filtration, M membranes exhibited higher water flux recovery ratio (FRR) value than that of m membranes and neat PES membrane.