Photochemical removal of NO2 in air at atmospheric pressure using side-on type 172-nm Xe2 excimer lamp
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The photochemical removal of NO2 in air (1–20% O2) was studied using a side-on type 172-nm Xe2 excimer lamp. The removal rate of NO2 using the side-on lamp (SL), 37.5 min−1, was faster than that using a head-on lamp (HL), 5.4 min−1, with the same input power of 20 W by a factor of 6.9. The energy efficiency for removal of NO2 using the SL was 3.2 g/kWh, which was 12 times higher than that using the HL. Significant enhancement of the removal rate and the energy efficiency using the SL was attributed to a significant increase in the irradiation volume because of a wider irradiation window. Under the SL irradiation, HNO3 was a major final product that differed from N2O5 obtained under the HL irradiation. To obtain the information related to the conversion mechanism of NO2 to HNO3 under 172-nm photolysis in air, computer simulation of the reaction processes was conducted. Results show that the OH + NO2 reaction is a major pathway for the formation of HNO3 in the SL, where OH radicals are formed by 172-nm photolysis of H2O.
KeywordsNO2 removal VUV photolysis Excimer lamp Kinetic model simulation
Fourier transform infrared
Taiyo Nippon Sanso
The authors wish to thank all who assisted in conducting this work.
Compliance with ethical standards
Conflict of interest
The authors have declared no conflict of interest.
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