End-of-Life Management Strategies for Fe–Mn Nanocomposites Used in Arsenic Removal from Water

This study investigates the regeneration, reuse, stabilization, and environmental safety of Fe-Mn polymer nanocomposites for arsenic (As) removal and their environmental safety. The regeneration performance of Fe-Mn polymer nanocomposites (PS-FMBO) used in this study was assessed through batch adsorption-desorption cycles using various eluents, including NaOH, NaOH-NaCl, and NaOH-NaOCl mixtures. The results demonstrated that 0.1 M NaOH yielded the best regeneration performance, maintaining higher adsorption efficiency over multiple cycles. Stronger desorption agents caused a significant decline in removal efficiency due to possible structural degradation of the PS-FMBO nanocomposite, suggesting that aggressive desorption conditions could compromise its long-term effectiveness. The stabilization of PS-FMBO with cement and quicklime was evaluated for immobilizing As, iron (Fe), and manganese (Mn). Leaching tests indicated that the composites effectively immobilized these contaminants, with minimal leaching observed even after prolonged aging, ensuring compliance with environmental safety regulations. Furthermore, chitosan-based foams were analyzed for their chemical stability, with leaching tests confirming low concentrations of As, Fe, and Mn, even under aggressive conditions, further reinforcing the material's safety and environmental compliance. These findings underscore the potential of PS-FMBO composites and chitosan-based foams as sustainable materials for hazardous waste management and eco-friendly construction applications. Their ability to immobilize contaminants while maintaining structural integrity highlights their practical significance in reducing environmental pollution and advancing circular economy principles.