Facile synthesis of hyperbranched magnetic nanospheres for highly efficient removal of methyl orange

Abstract

Amino-terminated hyperbranched polymer (ATHP1) coated magnetic microspheres (Fe₃O₄–ATHP1) was synthesized using amino-modified ferric tetroxide (Fe₃O₄–NH₂) as the core and glutaraldehyde as a cross-linking agent. The adsorption properties of Fe₃O₄–ATHP1 and Fe₃O₄–NH₂ for methyl orange (MO) adsorption were investigated and compared. ATHP1 functionalization was found to significantly improve the MO adsorption properties of the magnetic material. It was proved that Fe₃O₄–ATHP1 exhibited excellent adsorption performance at pH values ranging from 3 to 10 and in concentrations ranging from 10 mg L⁻¹ to 50 mg L⁻¹. Besides, easy separation and good recyclability were also observed for Fe₃O₄–ATHP1; after six cycles, it still had an over 78% removal capacity for methyl orange. The adsorption mechanism was also studied, and the MO adsorption mechanism on Fe₃O₄–ATHP1 followed the pseudo-secondary kinetic model and the Langmuir adsorption isothermal model.