The modification of carbon materials with carbon disulfide for the removal of Pb2+

Carbon spheres (CSs) were prepared with hydrothermal method, and multiwall carbon nanotubes (MWCNTs) and graphites were oxidized with Hummer's method. The obtained CSs, oxidized CNTs (OCNTs) and graphene oxides (GOs) included the oxygen-containing functional groups on these zero, one and two dimensional carbon materials. Carbon disulfide (CS2) was used to react with oxygen-containing groups for the formation of xanthate groups, which could produce the chelation structure with Pb2 +. The effect of CS2 dosage on the Pb2 + adsorption kinetic and isotherm of the modified CSs, OCNTs and GOs was investigated. The kinetic adsorption fit the pseudo-second-order model and the isotherm data followed the Langmuir model well. The maximum adsorption capacities for Pb2 + were 250.0, 357.1 and 500.0 mg/g for the modified CSs, OCNTs and GOs, respectively. These CS2-modified carbon materials were competitive with other absorbents for the heavy metal ions. Although the Pb2 + adsorption decreased much with the increasing of adsorption-desorption cycle times, these carbon materials still exhibited the good Pb2 + adsorption capacity.