Preparation, Characterization of Graphite/Vanadium Oxide and Its Adsorption Properties for Methylene Blue Solution

The graphite/vanadium oxide composites were prepared by a carbothermal reduction method using V2O5 as the raw material and graphite powder as the reducing agent. The Methylene blue was used as a simulated pollutant, the adsorption properties of the prepared samples under different reduction conditions were systematically evaluated, and the samples prepared at the reduction temperature of 650 degrees C, reduction time of 60 min and graphite ratio of 18.03% were selected for characterization and as the target adsorbent. The microstructure and surface morphology were characterized by X- ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, high-resolution transmission electronic microscope and BET microporous analysis. The characterization results show that the phases of the samples consist of graphite, VO2 and a small amount of V6O13. And the vanadium oxides are dispersed on the lamellar graphite surface in the form of lumps, strips and radiations. The particle sizes of the samples range from a few microns to tens of microns. The BET specific surface area and pore volume of the graphite/vanadium oxide are 6.84 m2/ g and 0.02 cm3/ g, respectively, and most of the pore sizes are distributed in the mesoporous and macroporous regions. The adsorption experiments results show that the graphite/vanadium oxide has good adsorption performance on methylene blue in the pH range of 3-8, and the equilibrium adsorption amounts are above 200 mg/g. The adsorption process is in accordance with the Langmuir isotherm and quasi-secondary kinetic equations.