(593c) Understanding the Binding Mechanism of Mercury on Activated Carbon

Coal combustion power plants constitute a significant amount of mercury released into the atmosphere. Oxidized mercury is captured by wet scrubbers, while gaseous elemental mercury passes through the scrubbers readily. Particulate matter such as fly ash, unburned carbon and activated carbon can be used to capture elemental and oxidized mercury through adsorption processes. Activated carbon is currently used in many power plants effectively. Understanding the mechanism by which mercury adsorbs on activated carbon is crucial for developing improved capture technologies for mercury. In this study we examine the possible binding mechanism of mercury on activated carbon, by performing ab initio energetics calculations using Gaussian03. The activated carbon surface is modeled by a single graphene layer in which the edge atoms on the upper side are unsaturated in order to simulate the active sites. In some cases, chlorine atoms are placed at the edge sites to understand the effect of chlorine on mercury binding and to investigate a possible surface reaction between mercury and chlorine.