Removal of Hg-0 vapor from the simulated coal combustion flue gases with a commercial activated carbon was investigated using H2S. This method is based on the reaction of H2S and Hg over the adsorbents. The Hg-0 removal experiments were carried out in a conventional flow type packed bed reactor system in the temperature range of 80-150 degrees C using simulated flue gases having the composition of Hg-0 (4.9 ppb), H2S (0-20 ppm), SO2 (0-487 ppm), CO2 (10%), H2O (0-15%), O-2 (0-5%), N-2 (balance gas). The following results were obtained: in the presence of both H2S and SO2, Hg removal was favored at lower temperatures (80-100 degrees C). At 150 degrees C, presence of O-2 was indispensable for Hg-0 removal from H2S-SO2 flue gas system. It is suggested that the partial oxidation of H2S with O-2 to elemental sulfur (H2S + 1/2O(2) = S-ad + H2O) and the Clause reaction (SO2 + 2H(2)S = 3S(ad) + 2H(2)O) may contribute to the Hg-0 removal over activated carbon by the following reaction: S-ad + Hg = HgS. The formation of elemental sulfur on the activated carbon was confirmed by a visual observation. (c) 2005 Elsevier Ltd. All rights reserved.