Facile synthesis of Fe3O4-graphene@mesoporous SiO2 nanocomposites for efficient removal of Methylene Blue

Herein, we have developed a facile and low-cost method for the synthesis of novel graphene based nanosorbents. Firstly, well-defined Fe 3 O 4 nanoparticles were decorated onto graphene sheets, and then a layer of mesoporous SiO 2 were deposited on the surface of the Fe 3 O 4 -graphene composites. The obtained Fe 3 O 4 -graphene@mesoporous SiO 2 nanocomposites (denoted as MG@m-SiO 2 ) were characterized by scanning electron microscopic (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transformed infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The adsorptive property was investigated by using MG@m-SiO 2 as sorbents and Methylene Blue (MB), a common dye, as model of the organic pollutants. Adsorption kinetics, isotherms, thermodynamics as well as effects of pH and adsorbent dose on the adsorption were studied. The adsorption isotherms and kinetics are better described by Langmuir isotherm model and pseudo-second-order kinetic model, respectively. Thermodynamic studies suggest that the adsorption of MB onto the MG@m-SiO 2 is endothermic and spontaneous process. The results imply that the MG@m-SiO 2 can be served as a cost-effective adsorbent for the removal of organic pollutants from aqueous solutions.