The persistent contamination of water bodies by organic compounds, heavy metals, and pathogenic microorganisms represents a critical environmental and public health concern worldwide. In this context, polymer composite materials have emerged as promising multifunctional platforms for advanced water purification. These materials combine the structural versatility of natural and synthetic polymers with the enhanced physicochemical functionalities of inorganic fillers, such as metal oxides and clay minerals. This review comprehensively analyzes recent developments in polymer composites designed to remove organic, inorganic, and biological pollutants from water systems. Emphasis is placed on key removal mechanisms, adsorption, ion exchange, photocatalysis, and antimicrobial action, alongside relevant synthesis strategies and material properties that influence performance, such as surface area, porosity, functional group availability, and mechanical stability. Representative studies are examined to illustrate contaminant-specific composite designs and removal efficiencies. Despite significant advancements, challenges remain regarding scalability, material regeneration, and the environmental safety of nanostructured components. Future perspectives highlight the potential of bio-based and stimuli-responsive polymers, hybrid systems, and AI-assisted material design in promoting sustainable, efficient, and targeted water purification technologies.

This study investigates the development of a sustainable flame-retardant treatment for cotton fabrics using a hybrid coating composed of chitosan, phytic acid, APTES, and eggshell powder at concentrations of 2% and 4%, applied in one and two cycles. FTIR confirmed the deposition of the organic–inorganic layer through the appearance of characteristic bands. Thermogravimetric analysis (TGA/dTGA) revealed enhanced thermal stability for all treated samples, with increased char yield and a shift in the main cellulose degradation peak. Vertical flammability tests demonstrated that all coated fabrics achieved self-extinguishing behavior within 12 s, meeting NFPA 701 criteria. The 2% eggshell formulation with two applications (S2%-II) exhibited the best balance between flame retardancy and mechanical performance. Tensile tests indicated improved fiber cohesion for treated samples, while SEM micrographs confirmed uniform coating deposition and particle integration. Colorimetric analysis showed that the treatment did not cause a significant change in the natural color of the cotton. Although washing resistance remains a limitation due to the natural origin of the components, the samples remained stable over time without microbial growth or staining, suggesting potential for upholstery and covering fabrics not subjected to domestic washing. The results highlight the feasibility of using agro-industrial waste to create eco-friendly flame-retardant finishes for cotton textiles.

Textile wastewater is among the most challenging industrial effluents due to its complex composition, high pollutant load, and low biodegradability. Conventional treatment methods often fall short in achieving complete removal of dyes and emerging contaminants. Photocatalytic composite membranes have emerged as a promising solution by integrating membrane separation and advanced oxidation processes. This review provides a comprehensive overview of the design, fabrication, and performance of photocatalytic composite membranes for textile wastewater treatment. Key aspects include the types of photocatalysts employed, methods of incorporation into membranes, and their synergistic role in pollutant removal and membrane fouling mitigation. Recent advancements in materials science, such as visible-light-responsive catalysts, carbon-based nanocomposites, and self-cleaning surfaces, are discussed, along with current limitations related to catalyst stability, operational scalability, and cost. This review underscores the potential of photocatalytic composite membranes as a next-generation platform for sustainable and effective textile wastewater treatment.