Mercaptans are commonly present in natural gas. Their high corrosiveness make them the most undesirable sulfur compounds, so they should be removed because of harmful effects on the environment. Disodium phosphonate functionalized graphene oxide (GO-P(Na)2) nanocatalyst was synthesized and adsorption of mercaptan on nanocatalyst was studied in this work. The nanocatalyst was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy analysis. The experiments were carried out in a fixed-bed reactor and the effect of temperature and Gas Hour Space Velocity (GHSV) parameters on mercaptan removal under nanocatalyst were investigated, demonstrating that increasing the temperature and decreasing the GHSV improves the rate of the reaction. Moreover, the kinetic parameters relevant to catalytic reaction for mercaptan removal under nanocatalyst were reported. The experimental results displayed that the maximum of mercaptan removal was obtained under GO-P(Na)2 nanocatalyst at the temperature of 100∘C and GHSV of 1000[Formula: see text]h[Formula: see text]. The concentration of output mercaptan under nanocatalyst reduced from 16,800[Formula: see text]ppm to less than 25[Formula: see text]ppm.