| Sulfur compound, included in coal gas as raw material of industry production, can not only endanger human heath, but cause equipments and pipes corrosion and make catalyst poison and product quality decrease. So, it is essential to removal sulfur compound to several ppm level even sub-ppm. Activated carbon(AC)materials are widely used for dry-desulfurization due to their rich porous structure,high specific area and strong adsorptivity. Since sulfur compound can be adsorbed on surface of activated carbon as the original form or elemental sulfur after oxidation, activated carbon materials combine unusual properties of both physical adsorption and chemical adsorption including catalytic oxidation and catalytic transformation. However, it is found that there exists the formation of COS using AC desulfurization. The emission of COS can not only cause the decrease of AC desulfurization performance and make subsequent synthesis catalysts more easily poison than H2S. The formation of COS during AC desulfurization is opposite to desulfurization role.The formation of COS during AC desulfurization limits application domain of activated carbon adsorbents, thus it is necessary to study the rule of COS formation for express purpose of decreasing its formation. The previous studies mainly has focused on COS formation above 100℃. Few reports, I have not seen the study of COS formation using AC in the removal H2S at room temperature. In this paper, the formation of COS was investigated over several commercial activated carbon adsorbents under various atmospheres comprising of O2,H2O and O2/H2O at room temperature. The mechanism of COS formation was discussed according to the experimental results of various carbon source and sulfur species. Four commercial ACs were studied by FTIR,N2-adsorption,TPD and acid-base titration. The different properties among four AC were discussion, thereby the effect of AC on the formation were concluded. The basic data were provided for the research,development and application of activated carbon desulfurizers.The results of experiments conducted in the blank reaction tube showed that, there was no COS produced at the conditons of atmospheric pressure, 500ml/min flow rate, and the temperature below 100℃, when the gas component was either CO+N2+H2S, CO2+N2+H2S, CO+N2+O2+H2S or CO2+N2+O2+H2S. This revealed that, the COS formation without catalyst is very difficult in lower temperature. There is a maximum value of COS produced in the different atmosphere when loading the same activated carbon in the reaction tube. The results can be explained on the basis of the sufficient S source was supplied to formate COS by activated carbon at the particular time; at the same time, the efficiency of active center which lead to the COS formation reached the highest value. The effects of different kinds of atmosphere on COS formation were different. The exist of O2 can inhibit the formation of COS while H2O can promate the formation of COS. The amount of COS produced under the conditions of normal situation is less than other conditions.The effects of the properties of different activated carbon on COS formation as follows:First, The pore structure of activated Carbon.The yield of cos drops with the specific area. pore volume and microporous of AC increasing. second,The content of basic group on activated carbon surface.the yield of cos decreases with the surface basic increasing.
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