In this study, Ni/Al2O3 nanoparticles were synthesized with the citric acid sol–gel method. Next, polyvinyl chloride membranes were modified with various amounts of Ni/Al 2O3 NPs (0, 0.5, 1, 1.5, and 2 wt% of solid phase). Fabricated polyvinyl chloride-Ni/Al 2O3 nanocomposite membranes were applied for the removal of humic acid from wastewater in a submerged membrane system. According to the water contact angle and porosity analysis, the addition of nanoparticles to the polyvinyl chloride membrane led to higher porosity and hydrophilicity. Moreover, 1.5 wt% Ni/Al2O3 modified membrane exhibited the greatest hydrophilicity and porosity. Additionally, noted membrane displayed more pores, larger pores on the top surface, and larger macrovoids on the cross-sectional surface. The analysis of the surface revealed that the addition of nanoparticles resulted in a smoother surface. As well, 1.5 wt% Ni/Al2O3 modified membrane demonstrated the highest flux recovery ratio and humic acid rejection, with values of 84.8 and 94.3%, respectively. Also, 1.5 wt% Ni/Al2O3 modified membrane provided the greatest antifouling resistance and hydrophilicity, with an irreversible fouling ratio of 15.2%. Generally, addition of nanoparticles to polyvinyl chloride membrane caused the higher hydrophilicity, greater porosity, uniform dispersion, smoother surface, and subsequently better antifouling performance. Furthermore, among the fabricated membranes, 1.5 wt% Ni/Al2O3 modified membrane illustrated the best antifouling performance.
