Polyvinyl chloride (PVC)/SiO2 membranes were prepared and characterized for ultrafiltration of oily wastewater from Tabriz Oil Refinery. The results showed that the addition of SiO2 into the membranes increased the density of surface pores. The contact angle decreased from 78.89° for the PVC membrane to 63.16° for the 0.75% PVC/SiO2 membrane, indicating that the presence of SiO2 resulted in enhancement of hydrophilicity. In addition, the pure water flux of the membranes witnessed an increasing trend with increasing SiO2 content. The mechanical tensile strength of the membranes was enhanced as a result of the reinforcement effect of nanoparticles. The results of filtration revealed that the antifouling properties and rejection of the composite membranes were higher than those of the PVC membrane because of the presence of SiO2. Membrane M3 containing 0.75 wt.% SiO2 nanoparticles exhibited a rejection of 84.19%, a total fouling ratio (TFR) value of 31.7% and an irreversible fouling ratio (IFR) value of 6.4%. In general, PVC/SiO2 membranes exhibited acceptable performance and can be tested for separation applications.
