Immobilization of heavy metal using dithiocarbamate agent

This research explored the influence of synthesizing temperature and time on the generation of dithiocarbamate in the form of Na salts (DTC-Na). The product with the highest DTC-Na content occurred at intermediate parameters (60 degrees C and 6h). Light scattering analysis determined that the molecular weight of DTC-Na with water as solvent was 5x10(7) (weight average), indicating sizeable molecules. The ratio of the root mean square radius to the hydrodynamic radius is approximately 0.62, suggesting that the DTC-Na molecule has a compact conformation. Infrared (IR) analysis revealed that the bands' characteristic of dithiocarbamate groups appeared at around 1000-1500cm(-1), the intensity of which decreased after the chelating process. On the other hand, oxidation of amide groups in the organic chain of DTC-Na could not be excluded during the chelation process. Immobilization efficiency of Pb(II) ion in excess of interfering ions and at different pH values was investigated. It was determined that the chelation effect of dithiocarbamate towards lead(II) was almost the same over the entire pH range (3-11), suggesting that DTC could maintain stabilization within a broad range of pH value. The capability of DTC-Na to chelate heavy metals was not weakened by competing alkali and alkaline earth metal ions.