Preparation and characterization of EDTAD-modified magnetic-Fe₃O₄ chitosan composite: application of comparative adsorption of dye wastewater with magnetic chitosan

Ethylenediaminetetraacetic dianhydride (EDTAD)-modified magnetic-Fe₃O₄ chitosan (EMC), prepared using the cross-link agent glutaraldehyde and chemicals Fe₃O₄, chitosan, and EDTAD, was used to compare the adsorption of methylene blue (MB) with magnetic chitosan (MC). The composite structure was confirmed by multiple characterization techniques, including scanning electron microscopy (SEM), X-ray powder diffraction, Fourier transform infrared spectroscopy (FTIR), and potentiometric titration methods. The characterization results suggest that Fe₃O₄ particles successfully bound on the surface of chitosan, and the EDTAD thoroughly modified the MC. Furthermore, EMC had more amino, carboxyl, and hydroxy groups than typical MC. Adsorption conditions, such as pH values, initial concentrations of MB, reaction temperature, and contact time were systematically examined. In comparison, the maximum adsorption capacity of EMC was approximately twice as much as that of MC. The recovery efficiency for EMC was >80% using 0.1 M HCl as an eluent solution. Therefore, the results reported herein indicate that EMC is very attractive and imply a practical application for dye wastewater treatment.