A novel chelating resin with functional group containing S and N atoms was prepared using chloromethylated polystyrene and 2,5-dimercapto-1,3,4-thiodiazole (also called bismuththiol I, BMT) as materials. Its structure was characterized by infrared spectra and elementary analysis. The results showed that the content of the functional group was 2.07 mmol BMT g(-1) resin, 47% of which were in the form of monosubstitution (PS-BMT-1) and 53% in the form of double substitution (PS-BMT-2). The adsorption for mercury ion was investigated. The adsorption dynamics showed that the adsorption was controlled by liquid film diffusion. Increasing the temperature was beneficial to adsorption. The Langmuir model was much better than the Freundlich model to describe the isothermal process. The adsorption activation energy (E-a), DeltaG, DeltaH, and DeltaS values calculated were 18.56 kJ(.)mol(-1), -5.99 kJ(.)mol(-1), 16.38 kJ(.)mol(-1), and 37.36, J(.)mol(-1.)K(-1), respectively. The chelating resin could be easily regenerated by 2% thiourea in 0.1 mol(.)L(-1) HCl with higher effectiveness. Five adsorption-desorption cycles demonstrated that this resin was suitable for repeated use without considerable change in adsorption capacity. (C) 2004 Wiley Periodicals, Inc.