Volume 15, No. 5, October 2015, Pages 2094-2103 PDF(955 KB)
Simultaneous Control of Elemental Mercury/Sulfur Dioxide/Nitrogen Monoxide from Coal-Fired Flue Gases with Metal Oxide-Impregnated Activated Carbon
Chun-Hsiang Chiu1, Hong-Ping Lin2, Tien-Ho Kuo3, Shiao-Shing Chen1, Tien-Chin Chang1, Kai-Han Su1, Hsing-Cheng Hsi4
1 Institute of Environmental Engineering and Management, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Rd., Taipei 106, Taiwan
2 Department of Chemistry, National Cheng-Kung University, No.1, University Rd., Tainan 701, Taiwan
3 Department of Environmental Engineering, Tungnan University, No. 152, Sec. 3, Peishen Rd., Shenkeng District, New Taipei City 222, Taiwan
4 Graduate Institute of Environmental Engineering, National Taiwan University, No. 71, Chou-Shan Rd., Taipei 106, Taiwan
- Metal oxide impregnation caused changes in carbon physicochemical properties.
- CuOx/CAC had the greatest Hg0 removal efficiency under N2 and flue gas.
- Metal oxide-impregnated carbons possessed appreciable Hg0 removal at 350°C.
- VOx/CAC had the largest SO2 removal enhancement at 350°C.
- Adsorption may not be suitable for NO control with metal oxide-impregnated carbon.
This research investigated the effects of transition metal oxide impregnation on the physical/chemical properties and on the multipollutant (i.e., Hg0/SO2/NO) control of a commercial coconut shell-based activated carbon. V, Mn, and Cu oxides of 5 wt% as their precursor metal hydroxides were impregnated onto the activated carbon surface. After the transition metal oxide impregnation, the surface area and pore volume of activated carbon decreased. The surface morphology of activated carbons was similar prior to and after impregnation. Mn3+/Mn4+ and Cu+/Cu2+ were shown to be the major valence states presenting in the MnOx and CuOx/CAC samples, respectively. CuOx/CAC possessed the greatest Hg0 removal efficiency of approximately 54.5% under N2 condition and 98.9% under flue gas condition, respectively at 150°C. When the gas temperature increased to 350°C, the metal oxide-impregnated activated carbon still possessed appreciable Hg0 removal, especially for CuOx/CAC. The VOx/CAC had the largest SO2 removal enhancement of approximately 28.3% at 350°C. The NO removal of raw and impregnated activated carbon was very small under flue gas condition, indicating that adsorption of NO using metal oxide-impregnated activated carbon may not be a suitable route for NO control.
Elemental mercury; Multipollutant control; Metal oxide; Activated carbon; Coal combustion.