GREEN SYNTHESIS AND CHARACTERIZATION OF GRAPHITE OXIDE BY ORTHOGONAL EXPERIMENT

Graphite oxide (GO) was prepared with graphite flakes, KMnO4, and a mixture of concentrated H2SO4/H3PO4 by an improved green synthesis method. To obtain fully oxidized GO, an orthogonal array design L-9 was applied to select the optimum preparing conditions. The effects of the quantity of graphite, the quantity of KMnO4, reaction time, and temperature on the degree of oxidization of GO were evaluated by the orthogonal array design (OAD). The results show that the factors arranged in important order as the follows: reaction time, reaction temperature, the quantity of KMnO4, the quantity of graphite. Graphite oxide obtained at the optimal parameters by the improved method was characterized by UV-Vis, FT-IR, Raman spectrum, and XRD techniques, and compared with GO produced by the modified Hummers' method. The results indicate that the GO obtained by the improved green synthesis method has fewer defects in the basal plane and is more oxidized than the modified Hummers' method.