Fabrication and properties of ultrafiltration membranes composed of polysulfone and poly(1-vinylpyrrolidone) grafted silica nanoparticles

Membranes for ultrafiltration were prepared from polysulfone (PSf) composites with poly(1-vinylpyrrolidone) grafted silica nanoparticles (PVP-g-silica). For the synthesis of PVP-g-silica, hydroxyl terminated silica nanoparticles were reacted with (3-methacryloxypropyl)trimethoxysilane (γ-MPS) to form γ-MPS terminated silica nanoparticles (silica-MPS), which were further reacted with VP monomer. Formation of PVP-g-silica was confirmed by FT-IR, XPS, TGA, FE-SEM, and HR-TEM. PSf/PVP-g-silica membranes exhibited higher water flux than PSf membranes without any loss in solute rejection for membranes containing less than or equal to 5 wt% of PVP-g-silica. The water flux of a membrane containing 1 wt% PVP-g-silica was 2.3 times higher than that of PSf membrane. The hydrophilicity of the PSf/PVP-g-silica membrane also increased with increasing PVP-g-silica content. The hydrophilicity of the PSf/PVP membrane decreased with increasing retention time in a water bath, while the hydrophilicity of the PSf/PVP-g-silica membrane did not change with retention time. PSf/PVP-g-silica membranes exhibited enhanced fouling resistance in fouling experiments using nonionic surfactants.