Abstract：The epoxy chloropropane and O-carboxymethyl chitosan were used as raw material to synthesize epoxide O-carboxymethyl chitosan (OCMC), which was then composited with Fe3O4 and melamine (MA) to prepare the adsorbent of magnetic O-carboxymethyl chitosan (MA-OCMC/Fe3O4) modified by melamine. The chemical structure and functional groups were characterized by Fourier-transformed infrared spectroscopy (FT-IR). Moreover, the effect of different conditions on the adsorption of Zn2+ was discussed. The characteristics of its adsorption kinetics and adsorption isotherm model were also investigated. The results showed that the adsorption equilibrium was reached when the adsorption time was 60 min for 0.13 g of MA-OCMC/Fe3O4 in 100 mL of 100 mg/L ZnCl2 solution at pH 6.0. The adsorption behavior conformed to the characteristics of pseudo second-order kinetic model and Langmuir isotherm adsorption model, which indicated that the adsorption process belonged to monolayer chemical adsorption. The theoretical saturated adsorption capacity was 86.96 mg/g, which closed to saturated adsorption capacity of 86.48 mg/g. The adsorption efficiency for Zn2+ by MA-OCMC/Fe3O4 merely decreased by 5.2% after cyclic adsorption-desorption for 6 times, indicating that it had good performance of reusability. The proposed method was suitable for the treatment of wastewater containing Zn2+.
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