The synthesis and trapping properties of dithiocarbamate macromolecule heavy-metal flocculants (DMHMFs) were studied. DMHMFs were synthesized through the reaction of polymine with carbon disulfide under alkaline conditions. The dosage of sodium hydroxide, carbon disulfide, and polymine and the reaction temperature and time were studied in detail. The flocculants were detected and characterized with IR spectroscopy, ultra viol et-visible spectroscopy, and solubility measurements. The trapping and removal properties of DMHMFs with respect to some heavy-metal ions were also studied. The results showed that a proposed trapping agent had good trapping and removal properties with respect to some heavy-metal ions in a wide pH range. The removal rates of copper(II) and lead(II) were up to 99.44 and 98.74%, respectively. In comparison with traditional inorganic chemical precipitation agents, the formation and precipitation of the flocs were quicker, and the dosage of the trapping agent was lower. In addition, in the precipitation processes, other flocculants did not need to be added, so the treatment process was simple. (C) 2008 Wiley Periodicals, Inc.