Chitosan Modified Magnetic Carbon-Based Adsorbent: Preparation and Adsorption Mechanism for Cr(III)-EDTA in Water

The magnetic carbon. based material (Fe3O4@C) was prepared by using ferrocene, and chitosan (CS) modified Fe3O4@C composite adsorbent (Fe3O4@C-CS) was prepared. The characterization of Fe3O4@C-CS by innfrared spectroscopy (FTIR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS), and the adsorption performance for Cr(III)-EDTA water was systematically studied by initial concentrations, adsorption temperature, time, solution pH and cations. The results show that Fe3O4@C has been successfully functionalized by CS. Adsorption isotherm was in accordance with the Langmuir model and the theoretical maximum adsorption capacity was 12.63 mg.g(-1) at 25 degrees C, pH=4.0 and dosage of 0.4 g.L-1. The adsorption kinetics can be fitted well with the pseudo-second kinetic model, and adsorption behavior is a spontaneous endothermic process. Based on the XPS analysis and adsorption experiments, the electrostatic interaction and surface complexation was the main mechanism of Cr(III)-EDTA adsorption on Fe3O4@C- CS adsorbent. After four adsorption and desorption cycles, Fe3O4@C-CS still had high adsorption efficiency for Cr(III)-EDTA in water.