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MERCURIC CHLORIDE CAPTURE BY ALKALINE SORBENTS
Citation:
Gullett*, B K., S. B. Ghorishi, R. Keeney, AND F. E. Huggins. MERCURIC CHLORIDE CAPTURE BY ALKALINE SORBENTS. Presented at AWMA Conference, Salt Lake City, Utah, 6/18-22/2000.
Description:
The paper gives results of bench-scale mechanistic studies of mercury/sorbent reactions that showed that mercuric chloride (HgC12) is readily adsorbed by alkaline sorbents, which may offers a less expensive alternative to the use of activated carbons. A laboratory-scale, fixed-bed apparatus was used to study the effect of sorbent properties on HgC12 capture at 60, 100, and 140?C. The objective of the study was to determine the mechanism of HgC12 capture by alkaline earth sorbents and to determine if alkaline earth and alkaline earth metal sorbents are suitable alternatives to activated carbon for capture of oxidized Hg species. Hg capture was compared to the physical and chemical properties of 11 sorbents by correlative analysis to determine the most significant indicator of reactivity. Physical properties of surface area, porosity, particle size, and pore diameter, as well as chemical surface basicity, were insufficient measures of sorbent capacity at all three temperatures. The reactivity of alkaline earth and alkaline earth metal sorbents with HgC12 is proposed to involve formation of unidentate and/or bidentate complexes on acidic and basic surface sites. Surface basicity alone was an insufficient measure of sorbent capacity, supporting a theory that the acidic character of the surface was also important to formation of the bidentate complex.