A kind of heterogeneous hollow-fiber affinity filter membrane with a high chelating capacity for Hg2+ was prepared by phase separation with blends of a mercapto chelating resin and polysulfone as the membrane materials, N,N-dimethylacetamide as the solvent, and water as the extraction solvent. The adsorption isotherms of the hollow-fiber affinity filter membrane for Hg2+ were determined. The heterogeneous hollow-fiber affinity filter membrane was used for the adsorption of Hg2+ cations through the coordination of the mercapto group and Hg2+ cations, and the effects of the morphology and structure of the affinity membrane on the chelating properties were investigated. The chelating conditions, including the chelating resin grain size, pH value, concentration of the metallic ion solution, mobile phase conditions, and operating parameters, had significant effects on the chelating capacity of the hollow-fiber affinity filter membrane. The results revealed that the greatest chelatin capacity of the hollow-fiber affinity filter membrane for Hg2+ was 1090 mu g/cm(2) of membrane under appropriate conditions, and the adsorption isotherms of Hg2+ could be described by the Langmuir isotherm. The dynamic chelating experiments indicated that the hollow-fiber affinity membrane could be operated at a high feed flow rate and that large-scale removal of Hg2+ could be realized. (C) 2007 Wiley Periodicals, Inc.