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ELEMENTAL MERCURY ADSORPTION BY ACTIVATED CARBON TREATED WITH SULFURIC ACID
Citation:
Li, Y., S D. Serre**, C W. Lee*, AND B K. Gullett*. ELEMENTAL MERCURY ADSORPTION BY ACTIVATED CARBON TREATED WITH SULFURIC ACID. Presented at EPA/DOE/EPRI Megasymposium, Chicago, IL, 8/20-24/01.
Description:
The paper gives results of a study of the adsorption of elemental mercury at 125 C by a sulfuric-acid (H2S04, 50% w/w/ solution)-treated carbon for the removal of mercury from flue gas. The pore structure of the sample was characterized by nitrogen (N2) at -196 C and the t-plot method anlaysis. Thermogravimetric analaysis (TGA) was used to examine the thermal behaviors of the treated sample. Study results show that the H2S04-treated carbon has a very high elemental mercury capture capacity (27 mg/g) via a physisorption mechanism. The pore volume and surface area of the treated carbon were drastically reduced due to adsorption of the H2S04 in the micropores of the carbon, resulting in a narrower microporisity. A significant amount of water (H20) was found to remain in the carbon through hydrogen bonding with the H2S04 molecules. It is suggested that the elemental mercury adsorption capacity of the H2S04-treated carbon can be explained by the enhanced adsorption potential and enthalpy of adsorption. The enhancements may result either from the narrow microporisity due to overlapping of the adsorption field from the neighboring pore walls, or from the increased surface polarity with which coulombic contributions from polarization energy to the overall adsorption potential could be significant.