Photocatalytic and antifouling performance of g-C₃N₄, CeO₂, and ZnO-grafted PVDF/TiO₂ nanohybrid membranes: a...

This research presents the design of three innovative photocatalytic systems and comparatively evaluates their performance by incorporating semiconductor nanoparticles into polymeric membranes for efficient water remediation under visible light. A novel assembly of poly(vinylidene fluoride) (PVDF)-based membranes was designed via phase inversion combined with aminopropyltrimethoxysilane (APTMS) self-assembly for the integration of TiO₂ with g-C₃N₄, CeO₂, and ZnO. The fabricated nanocomposite membranes exhibited significantly enhanced photocatalytic degradation, ultrafiltration and antifouling performance. Among the developed membranes, the PVDF-TiO₂/g-C₃N₄ (PTG-5%) membrane containing two bilayers confirmed superior performance, exhibiting 14% higher bovine serum albumin (BSA) rejection compared to the pristine PVDF membrane, indicating improved antifouling properties. An optimal methylene blue (MB) removal efficiency of approximately 98.34% was achieved for 5 mg L^-1 after 60 min of irradiation. The degradation resembles pseudo-first-order kinetics (k = 0.038 min^-1) and proceeded through a spontaneous and endothermic pathway dominated by photogenerated holes and hydroxyl radicals. The process conditions were further optimized using a Box-Behnken design (BBD) through a response surface methodology (RSM) framework, considering variables such as solution pH, catalyst dosage, and initial dye concentration. The statistical model predicted an optimal MB degradation efficiency of approximately 93.89% at 5 mg L^-1 MB with an irradiation time of 117 min. Overall, the integration of functional nanoparticles into PVDF membranes provides a highly efficient, stable, and scalable photocatalytic system for advanced water treatment applications.