In this paper, adsorption characteristics of methyl mercaptan on virgin activated carbon and copper chloride impregnated activated carbons were studied by using a dynamic adsorption method in a fixed bed. The activated carbons were characterized by nitrogen adsorption, XRD, TGA and solubility tests. The impregnation of copper chloride on the activated carbon significantly enhanced the adsorption capacity of methyl mercaptan, despite a notable decrease in microporosity. It is likely that copper chloride may act as adsorption site for methyl mercaptan. Copper chloride on the activated carbon in a range of 3-20 wt% Cu content was present mostly in the amorphous form of CuCl2, according to the results of the solubility, XRD and TGA tests. Starting at 10 wt% in Cu loading, the adsorption capacity for methyl mercaptan decreases gradually. It is likely that a decrease in the degree of copper chloride dispersion and an accessibility of small pores may lead to the decrease in the adsorption capacity of the activated carbon for methyl mercaptan. (C) 2004 Elsevier Inc. All rights reserved.