Adsorption of Cu²⁺, Cd²⁺ and Pb²⁺ in wastewater by modified chitosan hydrogel

Heavy metal pollution is extraordinary critical, so it is urgent to develop an effective adsorbent to dispose of such pollution. Modified chitosan was combined with polyacrylic acid to form N-carboxymethyl chitosan hydrogel (NCS-hydrogel) adsorbent. The morphology and structure of NCS-hydrogel were analyzed and identified by infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis and other characterization methods. NCS-hydrogel adsorption was used to treat water pollution of Cu, Cd and Pb ions, and the influencing factors of adsorption performance were studied. The intrinsic mechanism of adsorption process was discussed by thermodynamic, kinetic and isotherm models. The results show that the adsorption process of metal ions by NCS-hydrogel meets the spontaneous monolayer chemisorption, and the adsorption process is accompanied by heat release.