Abstract
An experimental study on the regeneration of deactivated SCR catalysts was carried out using a microwave-assisted method containing three steps of washing with mixed liquid of ethanol and water, impregnating, and drying. After the regeneration treatment, NO conversion at 320 °C increased from 39 to 90 % and vanadium content increased by 62.2 %, which were much higher than those regenerated by the traditional method. The more impregnated vanadium was due to the fact that the rapid evaporation of mixed liquid inside the catalyst channels led to the enlargement of surface areas by creating more pores on the catalysts. Meanwhile, with the increasing concentrations of ethanol, the heating rate of the mixed liquid increased, and the volume after complete evaporation of the mixed liquid was gradually reduced. Since higher heating rate and lager volume after the liquid evaporation could help to create more pores, therefore, when the volume ratio of ethanol/mixed solution was 20 %, the catalyst obtained the maximum specific surface area, which significantly increased to ca. 123 % compared with the deactivated catalyst. In addition, the catalyst dried by microwave exhibited better catalytic activity than that dried in conventional oven. Therefore, this method showed great potential in industrial applications.
Similar content being viewed by others
References
Ania, C. O., Menendez, J. A., Parra, J. B., & Pis, J. J. (2004). Microwave-induced regeneration of activated carbons polluted with phenol. A comparison with conventional thermal regeneration. Carbon, 42, 1383–1387.
Ania, C. O., Parra, J. B., Menéndez, J. A., & Pis, J. J. (2005). Effect of microwave and conventional regeneration on the microporous and mesoporous network and on the adsorptive capacity of activated carbons. Microporous and Mesoporous Materials, 85, 7–15.
Bo, L., Quan, X., Wang, X., & Chen, S. (2008). Preparation and characteristics of carbon-supported platinum catalyst and its application in the removal of phenolic pollutants in aqueous solution by microwave-assisted catalytic oxidation. Journal of Hazardous Materials, 157, 179–186.
Busca, G., Lietti, L., Ramis, G., & Berti, F. (1998). Chemical and mechanistic aspects of the selective catalytic reduction of NOx by ammonia over oxide catalysts: A review. Applied Catalysis B: Environmental, 18, 1–36.
Çalışkan, E., Bermúdez, J. M., Parra, J. B., Menéndez, J. A., Mahramanlıoğlu, M., & Ania, C. O. (2012). Low temperature regeneration of activated carbons using microwaves: Revising conventional wisdom. Journal of Environmental Management, 102, 134–140.
Catalyst Regeneration-Reinhold NOx Conf 2006 presentation; Coalgix/ SCR-Tech: 2006.
Cha, C. Y., & Carlisle, C. T. (2001). Microwave process for volatile organic compound abatement. Journal of the Air and Waste Management Association, 51(12), 1628–1641.
Cha, C. Y., Wallace, S., George, A. H., & Rogers, S. (2004). Microwave technology for treatment of fume hood exhaust. Journal of Environmental Engineering, 130, 338–348.
Dabek, L. (2007). Microwave regeneration of activated carbon. Environment Protection Engineering, 33, 107–115.
Fang, C. S., & Lai, P. (1996). Microwave regeneration of spent powder activated carbon. Chemical Engineering Communications, 147, 17–27.
Hashisho, Z., Rood, M., & Botich, L. (2005). Microwave-swing adsorption to capture and recover vapors from air streams with activated carbon fiber cloth. Environmental Science and Technology, 39, 6851–6859.
Khodayari, R., & Odenbrand, C. (2001a). Regeneration of commercial TiO2–V2O5–WO3 SCR catalysts used in bio fuel plants. Applied Catalysis B: Environmental, 30, 87–99.
Khodayari, R., & Odenbrand, C. (2001b). Regeneration of commercial SCR catalysts by washing and sulphation: Effect of sulphate groups on the activity. Applied Catalysis B: Environmental, 33, 277–291.
Kobayashi, M., & Hagi, M. (2006). V2O5–WO3/TiO2–SiO2–SO42-catalysts: Influence of active components and supports on activities in the selective catalytic reduction of NO by NH3 and in the oxidation of SO2. Applied Catalysis B: Environmental, 63, 104–113.
Mattes, M. F. (2011). SCR catalysts regeneration. 2011 NOx-Combustion/PCUG Conference.
McMahon, W. J. (2006). Regeneration advances. Environmental Controls Conference.
Park, S. S., Hwang, E. H., Kim, B. C., & Park, H. C. (2000). Synthesis of hydrated aluminum sulfate from kaolin by microwave extraction. Journal of the American Ceramic Society, 83, 1341–1345.
Pirola, C., Bianchi, C. L., Di Michele, A., Diodati, P., Boffito, D., & Ragaini, V. (2010). Ultrasound and microwave assisted synthesis of high loading Fe-supported Fischer–Tropsch catalysts. Ultrasonics Sonochemistry, 17, 610–616.
Polaert, I., Ledoux, A., Estel, L., Huyghe, R., & Thomas, M. (2007). Microwave assisted regeneration of zeolite. International Journal of Chemical Reactor Engineering, 5, 1–12.
Price, D. W., & Schmidt, P. S. (1997). Microwave regeneration of adsorbents at low pressure: Experimental kinetics studies. Journal of Microwave Power and Electromagnetic Energy, 32, 145–154.
Reuss, J., Bathen, D., & Schmidt-Traub, H. (2002). Desorption by microwaves: Mechanisms of multicomponent mixtures. Chemical Engineering and Technology, 25, 381–384.
Sadler, R. N. W. (2011). Results of catalyst regeneration process to lower SO2 conversion; EPRI’s 2011 Workshop on SCR Austin.
Stadler, C. O. K. A. (2005). Microwaves in organic and medicinal chemistry. Weinheim: Wiley.
Wang, X. Z., Zheng, J. S., Fu, R., & Ma, J. X. (2011). Effect of microwave power and irradiation time on the performance of Pt/C catalysts synthesized by pulse-microwave assisted chemical reduction. Chinese Journal of Catalysis, 32, 599–605.
Wenz, F., Deneault, R., & Franklin, H. N. (2006). The goals, challenges and success of regeneration selective catalytic reduction catalyst. NC: Coalgix/SCR-Tech.
Wu, S., Zhang, S., & Yang, J. (2007). Influence of microwave process on photoluminescence of europium-doped strontium aluminate phosphor prepared by a novel sol–gel–microwave process. Materials Chemistry and Physics, 102, 80–85.
Acknowledgments
This work is supported by the National Science Foundation for Distinguished Young Scholars of China (Foundation No. 51125025), Development of China (863 Program) (No. 2013AA065401).
Conflict of interest
The authors declare no competing financial interest.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Qiu, K., Song, J., Song, H. et al. A novel method of microwave heating mixed liquid-assisted regeneration of V2O5–WO3/TiO2 commercial SCR catalysts. Environ Geochem Health 37, 905–914 (2015). https://doi.org/10.1007/s10653-014-9663-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10653-014-9663-y