Design and application of CAM ‐xanthate hydrogel for high‐capacity adsorption of copper and nickel ions

Water contamination by toxic heavy metals is a major environmental challenge, necessitating the development of efficient and sustainable adsorbents. In this study, a cellulose‐based CAM‐Xanthate hydrogel was synthesized and applied for the removal of Cu 2+ and Ni 2+ ions from aqueous solutions. Three hydrogel grades were prepared and evaluated for their swelling behavior, with CAM‐Xanthate‐2 showing the highest swelling capacity of 306.78 g/g in distilled water, 263.62 g/g in tap water, and 237.21 g/g in gray water after 670 min. The hydrogels were comprehensively characterized using UV–Visible spectroscopy, FT‐IR, TGA, SEM, and point of zero charge (pHpzc) analysis. CAM‐Xanthate‐2 demonstrated excellent adsorption performance, achieving removal efficiencies of 96.36% for Cu 2+ and 94.44% for Ni 2+ ions. Adsorption equilibrium data followed the Langmuir isotherm model, with maximum adsorption capacities of 324.59 mg/g for Cu 2+ and 317.14 mg/g for Ni 2+ ions. Kinetic studies indicated that adsorption followed the pseudo‐second‐order model, with rate constants of 7.88 × 10 −4 and 7.78 × 10 −4 g/(mg·min) for Cu 2+ and Ni 2+ ions, respectively, suggesting a chemisorption‐controlled process. The hydrogel also exhibited good reusability, maintaining desorption efficiencies of 82.67% (Cu 2+ ) and 80.25% (Ni 2+ ) after 5 cycles. Overall, CAM‐Xanthate‐2 hydrogel showed strong potential as an effective, reusable, and sustainable adsorbent for the removal of heavy metals from contaminated water, with promising applicability in industrial wastewater treatment.