A comprehensive review of the functionalized polymer composite membranes in wastewater treatment

The growing demand for efficient wastewater treatment technologies has led to the development of modified polymeric composite membranes, offering improved separation performance, durability, and resistance to fouling. These membranes integrate base polymers with functional additives or coatings to address the limitations of conventional polymeric membranes, such as fouling, low selectivity, and limited mechanical stability. Base polymers, including polyethersulfone (PES), polyvinylidene fluoride (PVDF), and polysulfone (PSF), serve as foundational materials due to their chemical and mechanical properties. Additives such as nanomaterials (e.g., graphene oxide, carbon nanotubes), inorganic fillers (e.g., TiO₂, ZnO), and biopolymers (e.g., chitosan, cellulose) are incorporated to enhance functionality. Various modification techniques, including blending, layer-by-layer assembly, chemical grafting, and surface coating, allow the tailoring of membrane properties such as hydrophilicity, porosity, and antifouling capabilities. Modified membranes are applied across various filtration processes, including microfiltration, ultrafiltration, nanofiltration, and reverse osmosis, to achieve efficient removal of suspended solids, heavy metals, dyes, and organic pollutants. Recent innovations focus on antifouling, adsorptive, and photocatalytic membranes that exhibit superior performance and longevity. Despite significant advancements, challenges such as scalability, long-term stability, and environmental impact persist. Future directions emphasize the development of eco-friendly materials, sustainable fabrication methods, and smart membranes with self-cleaning or responsive properties. The integration of these membranes with other treatment technologies, such as advanced oxidation processes, could further enhance wastewater treatment efficiency. This paper reviews the preparation methods, material innovations, and application advancements in modified polymeric composite membranes for wastewater treatment.