Preparation of corn starch/acrylic acid/itaconic acid ion exchange hydrogel and its adsorption properties for copper and lead ions in wastewater

In this study, corn starch/acrylic acid/ itaconic acid (CS/AA/IA) hydrogel was prepared by solution polymerization, and then alkaline washed with sodium hydroxide solution to form corn starch/acrylic acid/ itaconic acid (CS/AA/IA) ion exchange hydrogel for the adsorption of copper and lead ions in aqueous solution. The structure and morphology of the hydrogel were characterized by Fourier transform infrared, X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The effects of contact time, initial concentration, temperature, pH, coexisting ions and different water types on the adsorption of Pb2+ and Cu2+ were analyzed by batch adsorption experiments. The CS/AA/IA ion exchange hydrogel reached adsorption equilibrium within 40 min. The maximum adsorption capacities of Pb2+ and Cu2+ fitted by the Langmuir isothermal adsorption model were 869.56 mg/g and 699.31 mg/g, respectively. After five adsorption-desorption cycles, the adsorption capacity of the hydrogel for Pb2+ and Cu2+ remained at 95%. The synthesis method maximized the conversion of –COOH in the hydrogel into the active group –COONa, forming a highly efficient adsorption hydrogel with ion exchange as the main effect. The CS/AA/IA ion exchange hydrogel exhibits high adsorption capacity, fast adsorption efficiency and remarkable regeneration property, and shows potential applications in the field of water treatment.