The purpose of the current study is to evaluate the mercury removal ability of F400 and Norit FGD activated carbons, through fixed bed adsorption tests at inert atmosphere (Hg degrees + N-2) Additionally, adsorption tests were realized on F400 activated carbon, in the presence of HCl, O-2, SO2 and CO2 in nitrogen flow. The obtained results, revealed that F400 activated carbon, with a high-developed micropore structure and increased BET area, exhibit larger Hg degrees adsorptive capacity compared to Norit. HCl and O-2, can strongly affect mercury adsorption. owing to heterogeneous oxidation and chemisorption reactions. which is in accordance with the assumptions of some researchers. Additionally, SO2 presence enhances mercury adsorption, in contrast with the Conclusions evaluated in other studies. The above result could be attributed to the possible formation of sulphur spaces on activated carbon surface and consist of a clarification for the role of SO2 on mercury adsorption. On the contrary. he mercury adsorption efficiency of F400 activated carbon showed a decrease at about 25%, with increasing CO2 concentration from 0 to 12%. (C) 2009 Elsevier B.V. All rights reserved.