One-pot solvothermal preparation of magnetic reduced graphene oxide-ferrite hybrids for organic dye removal

A one-pot solvothermal synthesis method was developed to prepare reduced graphene oxide (RGO) supported ferrite (MFe2O4, M = Mn, Zn, Co and Ni) hybrids using graphite oxide and metal ions (Fe3+ and M2+) as starting materials. The hybrids were characterized by X-ray powder diffraction, Raman spectra, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, and vibrating sample magnetometer. It was shown that monodispersed MFe2O4 microspheres with uniform size were homogeneously deposited on RGO nanosheets. The influence of the metal ion concentration on the morphology of the hybrids was investigated. The hybrids possess considerable saturation magnetization, lower remanence and coercivity. Importantly, the obtained hybrids are effective adsorbents for removal of dye pollutants. It was found that over 92% rhodamine B (RhB) and 100% methylene blue (MB) with a concentration of 5 mg/L can be removed by the hybrids within 2 min when the concentration of the hybrids is 0.6 g/L. In addition, the hybrids also show enhanced photocatalytic activity in the degradation of RhB and MB. Benefiting from their bigger saturation magnetization, the hybrids can be easily separated from the solution by a magnet. This research would provide a new easy separating platform for wastewater decontamination. (C) 2012 Elsevier Ltd. All rights reserved.