Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
582397 | Journal of Hazardous Materials | 2009 | 9 Pages |
Abstract
Photochemical removal of NO2 in N2 or air (5-20% O2) mixtures was studied by using 172-nm Xe2 excimer lamps to develop a new simple photochemical aftertreatment technique of NO2 in air at atmospheric pressure without using any catalysts. When a high power lamp (300 mW/cm2) was used, the conversion of NO2 (200-1000 ppm) to N2 and O2 in N2 was >93% after 1 min irradiation, whereas that to N2O5, HNO3, N2, and O2 in air (10% O2) was 100% after 5 s irradiation in a batch system. In a flow system, about 92% of NO2 (200 ppm) in N2 was converted to N2 and O2, whereas NO2 (200-400 ppm) in air (20% O2) could be completely converted to N2O5, HNO3, N2, and O2 at a flow rate of 1 l/min. It was found that NO could also be decomposed to N2 and O2 under 172-nm irradiation, though the removal rate is slower than that of NO2 by a factor of 3.8. A simple model analysis assuming a consecutive reaction NO2 â NO â N + O indicated that 86% of NO2 is decomposed directly into N + O2 and the rest is dissociated into NO + O under 172-nm irradiation. These results led us to conclude that the present technique is a new promising catalyst-free photochemical aftertreatment method of NO2 in N2 and air in a flow system.
Keywords
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Chemical Health and Safety
Authors
Masaharu Tsuji, Masashi Kawahara, Kenji Noda, Makoto Senda, Hiroshi Sako, Naohiro Kamo, Takashi Kawahara, Khairul Sozana Nor Kamarudin,