Reduction of nitrogen oxides by ozonization-catalysis hybrid process
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Treatment of nitrogen oxides (NOx) by using a hybrid process consisting of ozonization and catalysis was investigated. The ozonization method may be an alternative for the oxidation of NO to NO2. It was found that nitric oxide (NO) was easily oxidized to nitrogen dioxide (NO2) in the ozonization chamber without using any hydrocarbon additive. In a temperature range of 443 to 503 K, the decomposition of ozone into molecular oxygen was not significant, and one mole of ozone approximately reacted with one mole of NO. A kinetic study revealed that the oxidation of NO to NO2 by ozone was very fast, almost completed in a few tens of milliseconds. When the amount of ozone added was less than stoichiometric ratio with respect to the initial concentration of NO, negligible NO3 and N2O5 were formed. The oxidation of a part of NO to NO2 in the ozonization chamber enhanced the selective reduction of NOx to N2 by a catalyst (V2O5/TiO2), indicating that the mixture of NO and NO2 reacts faster than NO.
Key wordsNitrogen Oxides Ozonization Catalysis Hybrid Process
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- Hoard, J., “Plasma-Catalysis for Diesel Exhaust Treatment: Current State of Art,”Society of Automotive Engineers Technical Paper series, Paper number 01FL-63 (2001).Google Scholar
- Kogelschatz, U., “Advanced Ozone Generation,” Process Technologies for Water Treatment, Plenum Press, New York, 87 (1988).Google Scholar
- Manley, T. C., “The Electrical Characteristics of the Ozone Discharge,”Trans. Electrochem. Soc.,84, 83 (1943).Google Scholar
- Penetrante, B. M., Brusasco, R. M., Merritt, B. T. and Vogtlin, G. E., “Environmental Applications of Low-Temperature Plasmas,”Pure Appl. Chem.,71, 1829 (1999).Google Scholar
- Yoon, S., Panov, A. G., Tonkyn, R. G., Ebeling, A. C., Barlow, S. E. and Balmer, M. L., “An Examination of the Role of Plasma Treatment for Lean NOx Reduction over Sodium Zeolite Y. and Gamma Alumina Part 1. Plasma Assisted NOx Reduction over NaY. and Al2O3,”Catal. Today,72, 243 (2002).CrossRefGoogle Scholar