Effect of different forms of nano-ZnO on the properties of PVDF/ZnO hybrid membranes

In this article, polyvinylidene fluoride (PVDF)/ZnO hybrid membranes with different forms of nano-ZnO as additives were prepared by thermally induced phase separation. The effects of the morphology of ZnO particles on the microstructure and properties of hybrid membranes were systematically investigated. Three different forms of nano-ZnO were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Then a series of tests were made through XRD, Fourier transform infrared, differential scanning calorimeter, SEM, energy-dispersive X-ray spectroscopy, atomic force microscopy, mechanical strength testing, porosity measurement, water contact angle measurement, pure water flux measurement, rejection measurement, flux recovery rate (FRR) measurement, and photocatalytic degradation testing to characterize the hybrid membrane. The results show that the hybrid membranes which were doped with different forms of ZnO have different structures and properties. Porous ZnO has the best modification effect on PVDF membranes. The PVDF/porous ZnO hybrid membranes' water flux and OVA rejection can reach 1.6 and 1.3 times of pure PVDF membrane, respectively, and its FRR can reach about 95%. The hybrid membrane doped with porous ZnO has excellent self-cleaning performance, and its degradation rate of MB can reach about 51%.