Removal of Cu(II), Zn(II) and Pb(II) from water using microwave-assisted synthesized maghemite nanotubes

Magnetic maghemite ('gamma-Fe2O3) nanotubes were synthesized by microwave irradiation method and were used for the removal of Cu2+, Zn2+ and Pb2+ from water. The properties of this magnetic adsorbent were characterized by XRD, FESEM, HRTEM, zeta potential, BET surface area measurements and magnetization curves. Magnetic saturation of synthesized nanotubes was found to be 68.7 emu g(-1), and BET specific surface area was 321.638 m(2) g(-1). Adsorption experiments were carried out systematically by batch experiments to investigate the influence of different factors, such as contact time, initial concentration of metal ions, and pH of the solutions. The adsorption equilibrium study exhibited that the heavy metal ions adsorption of maghemite nanotubes followed a Langmuir isotherm model. The kinetic data of adsorption of heavy metal ions on the synthesized nano-adsorbents were best described by a pseudo-second-order equation, indicating their chemical adsorption. From the Langmuir isotherms, the maximum adsorption capacities of tubular maghemite adsorbents towards Cu2+, Zn2+ and Pb2+ were 111.11, 84.95 and 71.42 mg g(-1), respectively. This work demonstrates that synthesized maghemite nanotubes can be considered as potential magnetic nano-adsorbent. (C) 2012 Elsevier B.V. All rights reserved.