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

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.