Preparation of Zirconium Phosphate/Carboxymethyl Cellulose Composite Hydrogel for Cu²⁺ Removal

Zirconium phosphate (α-ZrP)/carboxymethyl cellulose (CMC) composite hydrogels were prepared through graft copolymerization by the easily scaling-up method. The α-ZrP/CMC hydrogels were characterized through FI-IR, SEM (EDS-SEM), XRD, TGA, BET, swelling and zeta potential measurements. The adsorption of Cu²⁺ by α-ZrP/CMC hydrogels in aqueous solutions was also studied. The results show that α-ZrP/CMC hydrogels have great adsorption capacity for Cu²⁺. The analysis results indicated that the adsorption mechanisms of α-ZrP/CMC hydrogel on Cu²⁺ are mainly through the electrostatic interaction. The adsorption process conforms to the Langmuir model (R² = 0.9953) and Quasi-second order kinetic model (R² = 1). Under the experimental conditions explored, the optimal amount of α-ZrP and the DS of CMC are chosen as 0.5 wt% and 1.2, and the adsorption capacity of ZrP-0.5%-CMC-1.2 hydrogel for Cu²⁺ is 121.21 mg/g. The adsorption isotherms, adsorption kinetics, and thermodynamics studies were also conducted to investigate the adsorption mechanism. Therefore, α-ZrP/CMC hydrogels present excellent adsorption efficiency, shows the potential application in future treatment of Cu²⁺ wastewater.