Influence on the structure and methylene blue adsorption of graphite oxide prepared by three modified Hummers methods

Graphite oxide (GO) was prepared by three improved Hummers methods (GO-1, GO-2, and GO-3). The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM), and the effects of different preparation methods on the adsorption of methylene blue by GO were studied. The results indicate that, with the increase of oxidant KMnO₄dosage and the extension of low temperature oxidation time, GO interlayer spacing gradually increases, in which the dosage of oxidant KMnO₄has a greater influence on the interlayer spacing. The increase of oxidant KMnO₄dosage will lead to the increase of oxygen-bearing functional groups and GO surface wrinkle, eventually resulting in an enlarge in the interlayer spacing. However, when the oxidant KMnO₄is overdosed, the adjacent surface of oxygen-bearing functional groups will be cross-linked, resulting in the stack of GO. Compared with GO-2 and GO-3, the removal efficiency of GO-1 to methylene blue is higher than that of GO-2 and GO-3 by 11.14% and 23.21%, respectively, indicating that the increase in oxygen-bearing functional groups will contribute to the adsorption of methylene blue on GO.