Dimensional effect of ZnO-g-C₃N₄ heterostructures on hydrophilic and anti-fouling properties of the PVDF/PAN composite membrane: Dye rejection

Bare polymer membranes face several limitations, including high fouling, low hydrophilicity, and high fouling resistance parameters. To overcome these challenges, modification methods such as adding polymer, monomer, inorganic, and other materials as additives are used. On the other hand, the type, gender, and morphology of additives are vital, owing to control of shape and size of pores, control of hydrophilicity, amount of dispersion in the membrane matrix, and overall improvement of membrane performance. In this research, ZnO-g-C₃N₄ heterostructures with different morphologies of ZnO were synthesized and added to the polymer membrane matrix. Several analyses confirmed the successful fabrication of membranes. The effect of the dimension (morphology) of the ZnO-g-C₃N₄ heterostructures on the dye removal and hydrophilic and anti-fouling properties of bare Polyvinylidene fluoride (PVDF)/Polyacrylonitrile (PAN) membrane was investigated. The 3 dimensional/2 dimensional (3D/2D) 18 wt% PVDF/PAN composite membrane with contact angle= 55.06º has pure water flux 95.8 L/m² h, Bovine serum albumin (BSA) flux 39.4 L/m² h, low resistance indexes, flux recovery ratio 87%, and rejection 95.3%, and 78.4%, for BSA and dye, respectively. Accordingly, 3D/2D 18 wt% PVDF/PAN composite membrane had better performance than other membranes owing to more hydrophilic properties, uniform and interconnected pores, and less surface roughness.