Affiliations: State Key Laboratory of Environmental Aquatic
Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of
Sciences, Beijing 100085, China | Department of Mechanical Engineering, Tsinghua
University, Beijing 100084, China
Abstract: Carbon nanotubes prepared by catalytic chemical vapor deposition of
hydrocarbon at 650°C show good adsorption capability of
Pb^{2+}, Cu^{2+} and
Cd^{2+} ions from aqueous solution after oxidized with
concentrated nitric acid at 140°C for 1 h. The specific surface area and
particle size distribution of the as-grown and oxidized CNTs were studied by
BET method and laser particle analyzer. Three kinetic models, that is, first-,
pseudo second- and second-order, were used to investigate the adsorption data
and the pseudo second-order model can represent the experimental data better
than two others. The equilibrium data fitted well with the Langmuir model and
showed the following adsorption order: Pb^{2+} >
Cu^{2+} > Cd^{2+}.
Keywords: carbon nanotubes, heavy metals, adsorption
