An amino-functionalized magnetic nano-adsorbent (MNPs-NH2) has been prepared by a simple one-pot method for the removal of Pb (II). These amino-functionalized Fe3O4 nano-particles showed a high adsorption capacity and efficient adsorption toward Pb (II) in an aqueous medium. The studies on the adsorption of Pb (II) ions revealed that the process obey the pseudo-second order kinetic model, the determining step might be chemical sorption. Among the various isotherm models, the experimental data for the adsorption of Pb (II) were found to follow the Langmuir isotherm and the maximum adsorption capacity was 40.10 mg g(-1) at pH 5 and 298 K. The sorption mean free energy from the Dubinin-Radushkevich isotherm was found to be 10.31 kJ mol(-1), indicating a chemical sorption. In addition, Pb (II) ions could be desorbed from nano-adsorbents and the MNPs-NH2 exhibited a good reusability. Importantly, about 98% of Pb (II) could be removed by MNPs-NH2 from industrial wastewater and tap water. (C) 2012 Elsevier B.V. All rights reserved.