Fe3O4-wheat straw: preparation, characterization and its application for methylene blue adsorption

The removal of methylene blue (MB) from aqueous solution by NaOHtreated wheat straw from agriculture biomass impregnated with Fe3O4 magnetic nanoparticles (MNP-NWS) was investigated. Magnetic nanoparticles (Fe3O4) were prepared by chemical precipitation of a mixture of Fe-2 and Fe-3' salts from solution aqueous by ammonia. These magnetic nanoparticles of the adsorbent Fe3O4 were characterized by Field Emission Scanning Electron Microscopy (FESEM), X-ray Diffraction (XRD), nitrogen physisorption and Fourier Transform Infrared Spectroscopy (FTIR). FIR results showed complexation and ion exchange appears to be the principal mechanism for MB adsorption. The adsorption isotherm data were fitted to Langmuir, Sips, Redlich-Peterson and Freundlich equations. Langmuir adsorption capacity, Q(max) was found to be 1374.6 mgg(-1). The Freundlich equation yielded the best fit to the experimental data in comparison to the other isotherm models. The removal of MB by MNP-NVVS followed pseudo -first -order reaction kinetics based on Lagergren equations. (C) 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.