X-ray photoelectron spectroscopy analysis of mercury sorbent surface chemistry

Laumb, Jason D.; Benson, Steven A.; Olson, Edwin A.

doi:10.1016/j.fuproc.2003.11.008

Cited by 58 publications

(46 citation statements)

References 4 publications

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“…Similar observations were also made in previous XPS studies of AC sorbents that also contained SO 2 and/or SO 3 in the flue gas. 13,14,32 The normalized amounts of S(VI) for the tested versus untested sorbents are as follows: 14.8% (TBP) vs 0.0% (UTBP), 5.0% (TSP) vs 0.4% (UTSP), and 1.5% (TSF) vs 0.7% (UTSF). Large increases in oxygen content accompanied the increase in the level of S(VI) species at a ratio of approximately 4:1, indicating that the S(VI) species formed during the capture process is SO 4 2− .…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Similar XPS studies were also performed on lignite AC by Laumb et al 14 and on brominated AC by Hutson et al 12 to understand the effect of flue gas components on the sorbent surface chemistry. Via combination of observations from bench-scale tests and XPS studies, it appears that the presence of both SO 2 and NO x in the flue gas mixture leads to rapid breakthrough of Hg, indicating poor Hg capture.…”

Section: ■ Introductionmentioning

confidence: 82%

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An X-ray Photoelectron Spectroscopy Study of Surface Changes on Brominated and Sulfur-Treated Activated Carbon Sorbents during Mercury Capture: Performance of Pellet versus Fiber Sorbents

Saha

Abram

Kuhl

et al. 2013

Environ. Sci. Technol.

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This work explores surface changes and the Hg capture performance of brominated activated carbon (AC) pellets, sulfur-treated AC pellets, and sulfur-treated AC fibers upon exposure to simulated Powder River Basin-fired flue gas. Hg breakthrough curves yielded specific Hg capture amounts by means of the breakthrough shapes and times for the three samples. The brominated AC pellets showed a sharp breakthrough after 170−180 h and a capacity of 585 μg of Hg/g, the sulfur-treated AC pellets exhibited a gradual breakthrough after 80−90 h and a capacity of 661 μg of Hg/g, and the sulfur-treated AC fibers showed no breakthrough even after 1400 h, exhibiting a capacity of >9700 μg of Hg/g. X-ray photoelectron spectroscopy was used to analyze sorbent surfaces before and after testing to show important changes in quantification and oxidation states of surface Br, N, and S after exposure to the simulated flue gas. For the brominated and sulfur-treated AC pellet samples, the amount of surface-bound Br and reduced sulfur groups decreased upon Hg capture testing, while the level of weaker Hg-binding surface S(VI) and N species (perhaps as NH 4 + ) increased significantly. A high initial concentration of strong Hg-binding reduced sulfur groups on the surface of the sulfur-treated AC fiber is likely responsible for this sorbent's minimal accumulation of S(VI) species during exposure to the simulated flue gas and is linked to its superior Hg capture performance compared to that of the brominated and sulfur-treated AC pellet samples.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 82%

An X-ray Photoelectron Spectroscopy Study of Surface Changes on Brominated and Sulfur-Treated Activated Carbon Sorbents during Mercury Capture: Performance of Pellet versus Fiber Sorbents

Saha

Abram

Kuhl

et al. 2013

Environ. Sci. Technol.

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“…This is partly due to the heterogeneous characteristics of the fly ashes and their generally low carbon content. When evaluating the role of carbon particles and the influence of gas composition, the interactions between the gas species and the surface of the activated carbons should be taken into account [19][20]. In combustion atmospheres, it has been observed that chlorine and sulfur species may be absorbed onto the surface of activated carbons and that these species may modify the surface and influence Hg retention [21].…”

Section: Because the Different Modes Of Occurrence Of Hg Involve Diffmentioning

confidence: 99%

The role of unburned carbon concentrates from fly ashes in the oxidation and retention of mercury

Abad-Valle

López-Antón

Dı́az-Somoano

et al. 2011

Chemical Engineering Journal

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“…Similar spectra were also obtained for Norit FGD and North Dakota lignite-derived carbons exposed to flue gas containing much larger amounts of HCl (50 ppm), but did not appear in spectra from a similar carbon exposed to flue gas that did not contain HCl. 15 Because of its very low concentration in the sample and instrumental interference of silicon, Hg was not detected on the surface; therefore, direct analysis of mercury bonding cannot be determined by this technique at these low concentrations, even at the maximum Hg capture capacity of the sorbent.…”

Section: Olson Crocker Benson Pavlish and Holmesmentioning

confidence: 99%

“…15 The experiments were intended to study the behavior in a relatively high HCl concentration (50 ppm) in the gas stream that would be representative of high-Cl coal combustion gases. That investigation clearly demonstrated that sulfur [S(VI)] builds up on the sorbents on exposure to flue gas, and, furthermore, both NO 2 and H 2 O are necessary for oxidation of the bound SO 2 to S(VI).…”

Section: Introductionmentioning

confidence: 99%

Surface Compositions of Carbon Sorbents Exposed to Simulated Low-Rank Coal Flue Gases

Olson

Crocker

Benson

et al. 2005

Journal of the Air & Waste Management Association

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Bench-scale testing of elemental mercury (Hg 0 ) sorption on selected activated carbon sorbents was conducted to develop a better understanding of the interaction among the sorbent, flue gas constituents, and Hg 0. The results of the fixed-bed testing under simulated lignite combustion flue gas composition for activated carbons showed some initial breakthrough followed by increased mercury (Hg) capture for up to ϳ4.8 hr. After breakthrough, the Hg in the effluent stream was primarily in an oxidized form (Ͼ90%). Aliquots of selected activated carbons were exposed to simulated flue gas containing Hg 0 vapor for varying time intervals to explore surface chemistry changes as the initial breakthrough, Hg capture, and oxidation occurred. The samples were analyzed by X-ray photoelectron spectroscopy to determine changes in the abundance and forms of sulfur, chlorine, oxygen, and nitrogen moieties as a result of interactions of flue gas components on the activated carbon surface during the sorption process. The data are best explained by a competition between the bound hydrogen chloride (HCl) and increasing sulfur [S(VI)] for a basic carbon binding site.

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X-ray photoelectron spectroscopy analysis of mercury sorbent surface chemistry

Cited by 58 publications

References 4 publications

An X-ray Photoelectron Spectroscopy Study of Surface Changes on Brominated and Sulfur-Treated Activated Carbon Sorbents during Mercury Capture: Performance of Pellet versus Fiber Sorbents

An X-ray Photoelectron Spectroscopy Study of Surface Changes on Brominated and Sulfur-Treated Activated Carbon Sorbents during Mercury Capture: Performance of Pellet versus Fiber Sorbents

The role of unburned carbon concentrates from fly ashes in the oxidation and retention of mercury

Surface Compositions of Carbon Sorbents Exposed to Simulated Low-Rank Coal Flue Gases

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