Preparation of novel polymethacryloyl hydrazone modified sodium alginate porous adsorbent with good stability and selective adsorption capacity towards metal ions

Manufacturing highly efficient, stable, and eco-friendly adsorbents for removing metal ions from wastewater remains a substantial and long-term challenge. Herein, a new polymethacryloyl hydrazone modified sodium alginate adsorption material (GSH) was successfully prepared by condensation between the polyhydrazide and dialdehyde sodium alginate. The morphology structure, specific surface areas, thermal stability, and functional groups of as-resulting adsorbent have been exhaustively examined by various characterization methods. Then, the prepared material was applied for the effective removal of metal ions, including Ni2+, Cu2+, Co2+, and Cr3+. Under optimal experimental circumstances, the maximum adsorption capacity of Ni2+, Cu2+, Co2+, and Cr3+ at 298.15 K was 343.60, 302.14, 245.25, and 157.85 mg/g, respectively. The adsorption process correlated well with the Langmuir isotherm and pseudo-second-order kinetic model. The thermodynamic analysis revealed that the adsorption of the metal ions on GSH was an endothermic and spontaneous process. In addition, the as-prepared adsorbent also exhibited excellent selective adsorption and resistance to anion interference. As demonstrated in FT-IR, SEM-EDS, and XPS analyses, the adsorption mechanism was primarily attributed to the ion exchange, electrostatic interaction, and chelating effect. After six adsorption–desorption cycles, the removal rate of the prepared adsorbent showed no significant change. In brief, the prepared material exhibited good adsorption capacity, and high cycle performance, making it a broad application prospect material in water remediation.