Effect of mixed SiO₂ nanoparticle/TiO₂ sol on structure and performance of PVDF composite membranes

Mixed TiO₂ sol and SiO₂ nanoparticles in different proportions were added into PVDF membrane, and their effects on pure water flux, retention rate and mechanical properties of PVDF membrane were discussed. The SiO₂-TiO₂/PVDF membrane surface and section structures were characterized by SEM, FT-IR, and XRD analyses. In addition, membrane mechanical properties and hydrophilicity were tested. The results indicated that mixed TiO₂ sol and SiO₂ nanoparticles could increase both hydro-philic and mechanical strength of PVDF membrane. When the SiO ₂/TiO₂ mixed ratio was 3:10, membrane performance was optimized (porosity 81%, flux 13.9 L-m²·h ^-1·KPa, retention rate 78%, tensile strength maximum loading 50N, tensile stress 3.18MPa, tensile strain 18%).