Sulfhydryl-Functionalized Reduced Graphene Oxide and Adsorption of Methylene Blue

The bonds of chlorine and carbon in chlorine-functionalized reduced graphene oxide (RGO) can provide reactive handles for modifications. In this work, sulfhydryl-functionalized RGO was synthesized using chlorine-functionalized RGO and sodium hydrosulfide. The product was characterized by Raman spectroscopy, Fourier-transform infrared spectroscopy, powder X-ray diffraction, and X-ray photoelectron spectroscopy. Some chlorine atoms were substituted and others were eliminated. The sulfhydryl group was successfully attached to a graphene sheet. It served as a spacer or pillaring agent between graphene sheets; the average interlayer space of the product was higher than that of RGO, the average interlayer space of graphitic material should be influenced by both pillaring agent and its amount. The sulfhydryl group may improve the adsorption capacity. High adsorption capacities are observed at a pH of 8-9. Removal efficiency of Methylene Blue (MB) was not affected by sodium and potassium ions. For magnesium and calcium ions, removal efficiency slightly decreased. The product had an adsorption capacity of 197.1mg/g for MB, which was higher than those of RGO (78.2mg/g) and commercial activated carbon (47.3mg/g) at ambient temperature. Adsorption capacity was also high at a high temperature.