Enhancement of Pb2+ removal by activating carbon spheres/activated carbon composite material with H2O vapor

H2O vapor was used to activate the carbon spheres/activated carbon (C-spheres/AC) to enhance its adsorption performance and prepare a composite of activated carbon spheres embedded in activated carbon (AC(spheres)/AC). The influence of H2O vapor activation on morphology, pore structure and surface element composition of C-spheres/AC were studied by scanning electron microscope, fourier transform infrared spectroscopy, N-2 sorption and X-ray photoelectron spectroscopy. It was found that the specific surface area was remarkably increased from 89.9 to 920.9 m(2)/g after activation, about 10 times, while the hydroxyl groups decreased from 46.2 to 35.6%. The adsorption behavior of Pb2+ was investigated and evaluated by Freundlich and Langmuir models. The result showed that the adsorption capacity was enhanced observably after activation and the maximum adsorption capacity of AC(spheres)/AC was achieved to 33.2 mg/g, about 3 times of C-spheres/AC.The adsorption process occurred on surface of absorbent was obeyed monolayer mechanism and in micro pores was multilayer adsorption. The specific surface area was main factor that affected the adsorption capacity. (C) 2016 Elsevier B.V. All rights reserved.