Improvement of Effectiveness and Photocatalytic Properties of Poly(vinylidene Fluoride)-TiO2-WO3 Membrane with Polydopamine Modification for Natural Rubber Wastewater Treatment

Abstract

This study investigates the enhancement of poly(vinylidene fluoride) (PVDF) membranes modified with TiO₂, tungsten trioxide, and coated with polydopamine (PDA) for rubber industry wastewater treatment. PDA coating improved the adhesion and dispersion of photocatalyst particles on the PVDF membrane. Membrane characterization using FTIR, SEM, SEM-EDX, XRD, mechanical strength, porosity, pore size analysis, water contact angle, and water uptake confirmed the structural and surface property enhancements of the PVDF-TiO₂-WO₃/PDA membrane, which contributed to improved pollutant rejection performance. The PVDF-TiO₂-WO₃/PDA membrane enhanced ammonia, phenol, chemical oxy­gen demand, and total dissolved solids rejection by 98.22%, 99.39%, 87.18%, and 51.06%, respectively, compared to the pristine PVDF membrane. After pretreatment, the flux value was 154.32 L/m²·h. The membrane exhibited the best photocatalytic degradation activity, with TiO₂-WO₃ nanoparticles enhancing pollutant removal under visible light and PDA coating contributing to enhanced selective permeability. Kinetic studies indicated that the zero-order kinetic model best describes photocatalytic activity. Membrane performance remained stable over five cycles, with high pollutant rejection despite some pore blockage and swelling. Overall, PDA modification on PVDF-TiO₂-WO₃ membranes offers a promising solution for efficient and environmentally friendly rubber wastewater treatment.