Development of a closed-loop process toward waste cotton textile upcycling into efficient ozonation catalysts for...

Upcycling waste cotton into high-value catalysts offers a more sustainable and promising alternative to conventional landfill disposal. In this study, a closed-loop upcycling process was established to converts waste cotton into efficient ozonation catalysts for the treatment and reuse of textile wastewater. Through a simple pyrolysis process, waste cotton textiles are transformed into carbonaceous catalysts (WCCs), with high-temperature treatment at 800 ℃ optimizing the mesoporous structure, graphitic carbon content, and defect density. These structural features significantly improve the surface reactants adsorption and facilitate the electron transfer. As a result, the WCC800/O₃ system exhibits a significantly higher p-nitrophenol (4-NP) removal efficiency with an observed pseudo-first-order kinetic rate constant (k_obs) of 0.221 min^-1, representing a improvement by 11.6 % over commercial activated carbon (AC)/O₃ system. Furthermore, WCC800 catalyst demonstrates strong resistance to interference from high-salinity and water-soluble organic matrices, making it well-suited for the advanced treatment of complex printing and dyeing (P&D) wastewater. The treated effluent meets quality standards for reuse in textile dyeing processes, thereby closing the loop in both waste cotton textile and wastewater recycling. Life cycle assessment (LCA) confirms a reduction in the environmental impacts associated with textiles disposal. This work presents a sustainable and circular strategy for the valorization of waste cotton in environmental remediation.