Application of g-C₃N₄/ZnO nanocomposites for fabrication of anti-fouling polymer membranes with dye and protein rejection superiority

Polysulfone (PSf) membranes are privileged for water and wastewater treatment, but because of their hydrophobic nature, they suffer from fouling, which lowers their performance and lifetime. In this work, g-C₃N₄ and g-C₃N₄/ZnO nanomaterials were synthesized via a hydrothermal method to modify the PSf membrane for effective dye separation and reduction of organic fouling. Since g-C₃N₄/ZnO possesses –OH and –NH reactive groups, g-C₃N₄/ZnO/PSf membrane revealed higher porosity, hydrophilicity, negative surface charge, and lower contact angle. The results of filtration analysis also showed a higher performance for nanomembranes with respect to the neat PSf. Permeability and fouling resistance of neat PSf membrane were well below those of nanocomposite membranes, such that by incorporation of 0.5 wt% g-C₃N₄/ZnO nanocomposite in PSf they significantly improved to 85.93 L/m² h bar and 90%, respectively. The rejection rate was also increased for both types of dyes used in this study (99.9% for Reactive green 19 and 85.5% for Reactive Yellow 160). The outcome of this research would suggest the application of graphitic nitride nanomaterials for developing highly efficient polymer membranes.