Abstract
A new approach to vapor phase elemental mercury capture has been explored; this approach exploits an ionic liquid coating layer to oxidize elemental mercury for subsequent immobilization by chelating ligands. The room temperature ionic liquid 1-butyl-1-methyl pyrrolidinium bis(trifluoromethane sulfonyl)imide (P14) was selected for study based on its oxidation potential window, thermal stability, and low vapor pressure. Tests were also completed in which KMnO4 was added to P14 to form a new ionic liquid, P14–KMnO4, with a higher oxidation potential. In room-temperature bulk liquid phase capture experiments, 59% of the elemental mercury in the inlet gas was captured using P14 alone; mercury capture using P14–KMnO4 was quantitative. P14 and P14–KMnO4 coatings were successfully applied to mesoporous silica substrates and to silica substrates functionalized with mercury chelating ligands. The coating layers were found to be thermally stable up to 300°C. Fixed-bed tests of nonfunctionalized silica coated with P14 showed an elemental mercury uptake of 2.7 mg/g adsorbent at 160°C; at the same temperature, functionalized silica coated with P14–KMnO4 showed an elemental mercury capacity of at least 7.2 mg/g adsorbent, several times higher than that of activated carbon. The empty bed gas residence time in these tests was 0.04 s. A chelating adsorbent incorporating P14 in the coating layer, may be capable of simultaneous removal of elemental and oxidized mercury from coal combustion flue gases.
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References
Abu Daabes, M. (2005). Synthesis and characterization of nano-structured chelating adsorbents for the direct removal of mercury vapor from flue gases. Dissertation, University of Cincinnati.
Abu Daabes, M., & Pinto, N. G. (2005). Synthesis and characterization of a nano-structured sorbent for the direct removal of mercury vapor from flue gases by chelation. Chemical Engineering Scence, 60, 1901–1910.
ASTM D6784-02 (2002). Annual book of ASTM standards, vol. 11.03. Water and Environmental Technology, ASTM International, PA, pp.1038–1054.
Benson, S. A., Laumb, J. D., Crocker, C. R., & Pavlish, J. H. (2005). SCR catalyst performance in flue gases derived from subbituminous and lignite coals. Fuel Processing Technology, 86, 577–613.
Bolger, P. T., & Szlag, D. C. (2002). An electrochemical system for removing and recovering elemental mercury from a gas stream. Environmental Science & Technology, 36, 4430–4435.
Cinzia, C., & Pieraccini, D. (2005). Review commentary ionic liquids: Solvent properties and organic reactivity. Journal of Physical Organic Chemistry, 18, 275–297.
Dastoor, A. P., & Larocque, Y. (2004). Global circulation of atmospheric mercury: A modelling study. Atmospheric Environment, 38, 147–161.
Granite, E. J., Pennline, H. W., & Hoffman, J. S. (1999). Effects of photochemical formation of mercuric oxide. Industrial and Engineering Chemistry Research, 38, 5034–5037.
Granite, E. J., & Pennline, H. W. (2002). Photochemical removal of mercury from flue gas. Industrial and Engineering Chemistry Research, 41, 5470–5476.
Helfritch, D., Harmon, G., & Feldman, P. (1996) Mercury vapor control by means of corona discharge. Paper 96-ES96.41 presented at the 89th Annual Meeting of the Air & Waste Management Association, Nashville, TN, June 23–28.
Huggins, F. E., Huffman, G. P., Dunham, G. E., & Senior, C. L. (1999). XAFS examination of mercury sorption on three activated carbons. Energy Fuels, 13, 114–121.
Krishnan, S. V., Gullett, B. K., & Jozewicz, W. (1994). Sorption of elemental mercury by activated carbons. Environmental Science & Technology, 28, 1506–1512.
Kumar, A., Jain, N., & Chauhan, S. M. S. (2004). Oxidation of benzylic alcohols to carbonyl compounds with potassium permanganate in ionic liquids. Synthetic Communications, 34, 2835–2842.
MacFarlane, D. R., Meakin, P., Sun, J., Amini, N., & Forsyth, M. (1999). Pyrrolidinium imides: A new family of molten salts and conductive plastic crystal phases. Journal of Physical Chemistry. B, 103, 4164–4170.
Nelson, S., Landreth, R., Zhou, Q., & Miller, J., (2003). Mercury sorbent injection test results at the Lausche plant. Paper presented at the DOE-U.S.EPA-EPRI-AWMA Power Plant Air Pollution Control “Mega” Symposium, Washington, DC, May 19–22.
O’Dowd, W. J., Hargis, R. A., Granite, E. J., & Pennline, H. W. (2004). Recent advances in mercury removal technology at the National Energy Technology Laboratory. Fuel Processing Technology, 85, 533–548.
Panchgalle, S. P., Choudhary, S. M., Chavan, S. P., & Kalkote, U. R. (2004). The oxidation of 4-alkyl and 4-aryl-1,4-dihydropyridines to pyridines with hydrogen peroxide in an ionic liquid. Journal of Chemical Research, 2004, 550–551.
Pavlish, J. H., Sondreal, E. A., Mann, M. D., Olson, E. S., Galbreath, K. C., Laudal, D. L., et al. (2003). Status review of mercury control options for coal-fired power plants. Fuel Processing Technology, 82, 89–165.
Pitoniak, E., Wu, C. -Y., Mazyck, D. W., Powers, K. W., & Sigmund, W. (2005). Adsorption enhancement mechanisms of silica-titania nanocomposites for elemental mercury vapor removal. Environmental Science & Technology, 39, 1269–1274.
Rao, G. V., Raman, S., & Singh, M. P. (Eds.) (2003). Air Quality. Basel: Birkhäuser.
Seigneur, C., Vijayaraghavan, K., Lohman, K., Karamchandani, P., & Scott, C. (2004). Modeling the atmospheric fate and transport of mercury over North America: Power plant emission scenarios. Fuel Processing Technology, 85, 451–462.
Sjostrom, S., Ebner, T., Ley, T., Slye, R., Richardson, C., Machalek, T., et al. (2002). Assessing sorbents for mercury control in coal-combustion flue gas. Journal of the Air and Waste Management Association, 52, 902–911.
US EPA (2005). Clean air mercury rule; http://www.epa.gov/air/mercuryrule/index.htm. 2005. Accessed Sept. 12, 2006.
Vidic, R. D., & Chang, M. T. (1998). Kinetics of vapor-phase mercury uptake by virgin and sulfur-impregnated activated carbons. Journal of the Air & Waste Management Association, 48, 247–255.
Xu, M., Yan, R., Zheng, C., Qiao, Y., Han, J., & Sheng, C. (2004). Status of trace element emission in a coal combustion process: A review. Fuel Processing Technology, 85, 215–237.
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The authors gratefully acknowledge the financial help from Ohio Coal Development Office through Grant OCRCIV B1.7.
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Ji, L., Thiel, S.W. & Pinto, N.G. Pyrrolidinium Imides: Promising Ionic Liquids for Direct Capture of Elemental Mercury from Flue Gas. Water Air Soil Pollut: Focus 8, 349–358 (2008). https://doi.org/10.1007/s11267-007-9144-8
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DOI: https://doi.org/10.1007/s11267-007-9144-8