Biowastes as sustainable catalysts for water treatment: A comprehensive overview

• Biowaste catalysts offer sustainable solutions for water purification • Synthesis methods like pyrolysis and hydrothermal carbonization affect efficiency • Contaminants such as heavy metals, pollutants, and emerging threats are removed • Challenges include stability, reusability, and scalability of bio-waste catalysts • Economic and environmental benefits emphasize cost-effectiveness and sustainability Water purification remains a critical global challenge that requires innovative and sustainable solutions. This review highlights the transformative potential of catalysts derived from biowaste for water treatment, offering eco-friendly and cost-effective alternatives to traditional methods. Agricultural residues, food waste, and biomass are converted into efficient catalysts through processes such as pyrolysis, hydrothermal carbonization, and chemical activation. These catalysts enable the removal of heavy metals, organic pollutants, and emerging contaminants through adsorption and oxidation mechanisms. They address both waste management and water treatment needs, aligning with circular economy principles by promoting resource recovery and sustainability. Integrating advanced technologies, such as membrane filtration and advanced oxidation processes, further enhances the efficacy of these catalysts. Additionally, artificial intelligence and machine learning provide tailored solutions for optimizing catalyst design and enabling real-time monitoring. Despite challenges related to scalability, stability, and reusability, strategies such as functionalization, hybridization, and the incorporation of computational tools offer pathways for improvement. This comprehensive review underscores the economic and environmental benefits of biowaste-based catalysts while identifying future research directions to advance this promising technology. It emphasizes the importance of green innovation in sustainable water purification.