Efficient removal of copper ions and organic dyes using chitosan, pectin, and magnetic hydrogel composites: Structural characterization and adsorption mechanisms

This study investigates the adsorption efficiencies of twelve hydrogel groups, including chitosan, pectin, sodium alginate, cypress, bitter ginseng, dandelion, persimmon leaf, and magnetic hydrogels, for the removal of copper ions, methylene blue, and congo red from aqueous solutions. The hydrogels were characterized using SEM, XRD, XPS, BET, VSM, TGA, FTIR, and DFT calculations to elucidate their structural and functional properties. Adsorption kinetics, isotherms, and mechanisms were thoroughly analyzed, with models fitted to the experimental data. Among the tested hydrogels, pectin-cellulose demonstrated the highest adsorption capacity for copper ions, Phellodendron-polysaccharide-cellulose for methylene blue, and magnetic cellulose-based hydrogels for congo red. This research highlights the potential of these innovative hydrogels as sustainable solutions for wastewater treatment, effectively addressing critical environmental challenges by removing hazardous substances. The findings provide valuable insights into the adsorption processes and contribute to the development of advanced materials for environmental remediation.