Graphene oxide has received world-wide attention due to its exceptional physicochemical properties. Herein, a sulfonated magnetic graphene oxide composite (SMGO) was synthesized from graphene oxide and was used as adsorbent for removing Cu(II) ions from aqueous solution. The composite was characterized by TEM, EDS, particles size, BET, TG-DTA, FT-IR, and Raman. It can be separated and recovered easily using magnetic separation technology. The effects of operating parameters such as pH, Cu(II) concentration and temperature on the Cu(II) adsorption were investigated by using a response surface methodology (RSM). Optimum Cu(II) uptake of 62.73 mg g(-1) was achieved at pH 4.68, Cu(II) concentrations 73.71 mg L-1, and temperature 50 degrees C. The adsorption process can be well described by the pseudo-second order kinetic model. The experimental data of isotherm followed the Langmuir isotherm model. Moreover, the thermodynamic parameters calculated from the temperature-dependent isotherms indicated that the adsorption reaction was an endothermic and spontaneous process. All results indicate that the SMGO is a promising adsorbent for the efficient removal of copper ions from wastewater. (C) 2013 Elsevier B.V. All rights reserved.