Study on the adsorption behavior of cadmium, copper, and lead ions on the crosslinked polyethylenimine dithiocarbamate material

In order to obtain a highly efficient solid-state heavy metal ion absorbing material, the crosslinked polyethylenimine dithiocarbamate was prepared via condensation of polyethyleneimine (PEI) with abundant amino groups and glutaraldehyde to form the crosslinked polymer, reduction of the resulting C=N double bonds to a much stable C-N single bonds, and then grafted with carbon disulfide. The material was evaluated in adsorbing cadmium (II), copper (II), and lead (II) ions. The adsorption behavior of cadmium, copper, and lead ions on the absorbent material was studied. Experiment results show that the adsorption rate is rapid for heavy metal ions, and the adsorption amount tends to constant after 40 min. Its absorption capabilities for cadmium (II), copper (II), and lead (II) ions reach up to 205.99, 215.02, and 451.79 mg/g, respectively. Furthermore, the absorbing material has good desorption and regeneration performance. The adsorption kinetics model well accords with the pseudo-second order kinetic equation. And the process of the adsorption is linear with the Langmuir adsorption model, and thus the adsorption process is monolayer adsorption.