A novel method of surface modification was developed via iron (III)-mediated atom transfer radical polymerization, with activators regenerated by electron transfer (ARGET ATRP) on the surfaces of polystyrene resin-supported N-chlorosulfonamide groups. The well-defined polyacrylonitrile (PAN) was grafted onto the surfaces of the polystyrene (PS). The graft reaction exhibited first-order kinetics with respect to the polymerization time in the low-monomer-conversion stage. The cyano group of PAN-g-PS was modified by NH2OH center dot HCl to yield amidoxime (AO) groups. The AO groups had been demonstrated to be an efficient Hg-specific sorbent, which can remove Hg2+ from solutions. No interference arose from common metal ions, such as Pd2+, Ag+, and Cu2+. Three adsorption-desorption cycles demonstrated that this resin is suitable for reuse without any considerable change in adsorption capacity. (C) 2010 Elsevier B.V. All rights reserved.