RESUMO
The effect of polydopamine (PDA) modification on aminated Fe3O4 nanoparticles (Fe3O4-NH2)/graphite oxide (GO)/ß-cyclodextrin polymer cross-linked by citric acid (CDP-CA) composites were studied for the removal of a cationic dye (methylene blue, MB) and an anionic dye (Congo red, CR) from waters. The micro-structural and magnetic characterizations confirmed the successful preparation of Fe3O4-NH2/GO/CDP-CA and PDA/Fe3O4-NH2/GO/CDP-CA composites. The maximum MB and CR adsorption capacities of Fe3O4-NH2/GO/CDP-CA were 75 mg/g and 104 mg/g, respectively, while the corresponding amounts for PDA/Fe3O4-NH2/GO/CDP-CA composite were 195 mg/g and 64 mg/g, respectively. The dye sorption behaviors of these two composites were explained by their corresponding surface-charged properties according to the measured zeta potential results. Moreover, the high saturation magnetizations and the stable dye removal rate in the adsorption-desorption cycles indicated the good recyclability and reusability of the fabricated composites.