Multifunctional SGCG/CuO2 composite hydrogel for integrated wastewater remediation: Copper ions removal, phenolic pollutant degradation, and bacterial inactivation.

Hydrogel-based materials have emerged as promising candidates for wastewater remediation due to their remarkable adsorption capacity, recyclability, and environmental compatibility. In this study, we developed a multifunctional sodium alginate-glutaraldehyde-chitosan-gelatin (SGCG) composite hydrogel with enhanced mechanical properties and abundant functional groups (-COOH, -NH2) for efficient Cu2+ sequestration. Investigation of adsorption parameters revealed optimal conditions and underlying mechanisms for heavy metal removal. Subsequent in situ reaction of the Cu2+-loaded hydrogel (SGCG/Cu2+) with H2O2 yielded a nanozyme composite (SGCG/CuO2) with dual enzyme-mimetic activities: laccase-like activity for phenolic pollutant degradation and peroxidase-like activity for antibacterial applications. The SGCG/CuO2 hydrogel exhibited exceptional performance in removing phenolic contaminants and inactivating pathogenic bacteria (Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli)), owing to its robust catalytic properties. This work presents an innovative multifunctional hydrogel system that integrates heavy metal adsorption, catalytic organic degradation, and antimicrobial activity into a single platform, offering a sustainable and efficient solution for complex wastewater remediation.