The EDTA functionalized magnetic nano-particles (MNPs-EDTA) as a novel magnetic nano-adsorbent have been prepared by a simple one-pot method for the removal of Cu(II) from aqueous solution. Factors affecting the adsorption of Cu(II) on MNPs-EDTA, such as contact time, temperature, pH, salinity, and initial concentration of Cu(II), were investigated. The studies on the adsorption revealed that the adsorption process obeyed the pseudo-second order kinetic model, the determining step might be chemical sorption and the adsorption equilibrium could be achieved in 5 min. Among the various isotherm models, the experimental data for the adsorption of Cu(II) followed the Langmuir isotherm best and the maximum adsorption capacities was 46.27 mg g(-1) at pH 6.0 and 298 K. Thermodynamic parameters declared that the adsorption process was endothermic and spontaneous. The removal efficiencies of Cu(II) were over 98.3% and inappreciably influenced by the water matrix. In addition, the adsorption-desorption studies indicated that MNPs-EDTA had a high stability and good reusability. (C) 2012 Elsevier B.V. All rights reserved.