Enhancing water flux and rejection performance through UV crosslinking: Optimization of surface modification of polyacrylonitrile (PAN)/acrylonitrile butadiene rubber (NBR) blend membrane using benzophenone as a crosslinking agent

Polyacrylonitrile (PAN)/acrylonitrile butadiene rubber (NBR) blend membranes were prepared by the phase inversion method using dimethylformamide as solvent. The blend membrane with a ratio of 85:15 was modified by ultraviolet (UV) radiation crosslinking of NBR using benzophenone as the crosslinking agent. The blend membrane was characterized through Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), porosity, contact angel, tensile strength, pure water flux, and rejection measurements. The blend membrane showed an increased pure water flux and decreased BSA rejection. However, the addition of benzophenone and UV radiation reduced the porosity and flux of the membrane, while improving the tensile strength and BSA rejection. The response surface method (RSM) with central composite design (CCD) using Design Expert software was employed to optimize the modification conditions of the PAN/NBR blend membrane, and the suggested membrane contained 2.5 wt% benzophenone and was exposed to UV radiation for 2 h. This membrane showed a pure water flux of 95.3 L/m2h, BSA rejection of 81.1%, and a tensile strength of 4.01 MPa, which is a 45% increase in water flux compared to the neat PAN membrane while showing better rejection and preserving the desired mechanical properties.