Development of a CI-impregnated activated carbon for entrained-flow capture of elemental mercury

Efforts to discern the role of an activated carbon's surface functional groups on the adsorption of elemental mercury (Hg0) and mercuric chloride demonstrated that chlorine (CI) impregnation of a virgin activated carbon using dilute solutions of hydrogen chloride leads to increases (by a factor...

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Bibliographic Details
Published in:Environmental science & technology 2002-10, Vol.36 (20), p.4454
Main Authors: S Behrooz Ghorishi, Keeney, Robert M, Serre, Shannon D, Gullett, Brian K, Jozewicz, Wojciech S
Format: Article
Language:English
Subjects:
Activated carbon
Carbon
Chlorine
Gases
Mercury
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Summary:Efforts to discern the role of an activated carbon's surface functional groups on the adsorption of elemental mercury (Hg0) and mercuric chloride demonstrated that chlorine (CI) impregnation of a virgin activated carbon using dilute solutions of hydrogen chloride leads to increases (by a factor of 2-3) in fixed-bed capture of these mercury species. A commercially available activated carbon (DARCO FGD, NORIT Americas Inc. [FGD]) was Cl-impregnated (Cl-FGD) [5 lb (2.3 kg) per batch] and tested for entrained flow, short-time-scale capture of Hg0 In an entrained flow reactor, the CI-FGD was introduced in HgO-Iaden flue gases (86 ppb of Hg0 of varied compositions with gas/solid contact times of about 3-4 s, resulting in significant Hg0 removal (80-90%), compared to virgin FGD (10-15%). These levels of Hg0 removal were observed across a wide range of very low carbon-to-mercury weight ratios (1000-5000). Variation of the natural gas combustion flue gas composition, by doping with nitrogen oxides and sulfur dioxide, and the flow reactor temperature (100-200 degrees Celsius had minimal effects on Hg0 removal by the Cl-FGD in these carbon-to-mercury weight ratios. These results demonstrate significant enhancement of activated carbon reactivity with minimal treatment and are applicable to combustion facilities equipped with downstream particulate matter removal such as an electrostatic precipitator.
ISSN:0013-936X