Recent studies show that carbonaceous materials have gained interest because of their superior features over the alternative adsorbents. Therefore, it is of great value to synthesize novel carbonaceous adsorbents. In the present study, graphene oxide nanopowders (GON) were synthesized through a modified Hummer's method. The material has been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) methods. Naproxen has been selected as the model pharmaceutical to investigate the adsorption performance of GON. The highest adsorption removal was found to be 65.28% under the optimum conditions (0.03 g of GON for the adsorption of 10 mg/L naproxen solution at 100 rpm mixing the speed of shaking bath). The relevant adsorption system was an exothermic, spontaneous, and chemisorption process depending on the kinetic (pseudo-first order, pseudo-second order, intraparticular, and Elovich models), equilibrium (Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Harkin-Jura, and Halsey isotherm equations), and thermodynamic parameters.