Preparation of monodisperse cross-linked PS-DVB-GMA-amino-Fe3O4 magnetic microspheres with Cu (II) ions removal property

Abstract

The monodisperse cross-linked PS-DVB-GMA-amino-Fe3O4 magnetic microspheres with functional group of amino were synthase by seed swelling method using PS microspheres as seeds, and glycidyl acrylate as monomer in the swelling polymerization; and then modified poly (styrene-glycidyl methacrylate) (PS-DVB-GMA) microspheres with ethylene diamine to form amino-groups; subsequently, Fe3O4 nanoparticles were grafted on the microspheres through in situ precipitation reaction. The morphology, composition, magnetic properties, and crystalline structure of the magnetic microspheres were characterized by scanning electron microscope with energy dispersive analysis of X-rays (SEM/EDX), transmission electron microscopy(TEM), vibrating sample magnetometer(VSM), X-ray diffraction(XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) methods, respectively. The resulting PS-DVB-GMA-amino-Fe3O4 magnetic microspheres were tested for their ability to remove copper (II) ions from an aqueous solution in batch experiments. The effects of adsorption time and pH value on the adsorbed dosage of copper ions on magnetic microspheres was investigated. Besides, two adsorption isotherm models (i.e., the Langmuir and the Freundlich models) were used to fit the experimental isotherm adsorption data. The average size of microspheres was 5.92 μm with the PDI was 0.024. The composite magnetic microspheres could be easily separated from solution by magnetic decantation using a permanent magnet. The adsorption experiments demonstrate that copper ions adsorption onto the PS-DVB-GMA-amino-Fe3O4 magnetic microspheres reaches a maximum after the 45 min. The maximum adsorption capacities (q e = 76.8 mg/g) was reached at the pH value of 5.0 when the temperature was 25 °C, and by simulating the experimental data with the Langmuir, the maximum equilibrium absorption capacity of PS-DVB-GMA-amino-Fe3O4 magnetic microspheres was 134.0216 mg/g, showing a good adsorptive property to Cu (II).