Degradation of indoor gaseous formaldehyde by hybrid VUV and TiO2/UV processes

Treatment of organic waste gas in a paint plant by combined technique of biotrickling filtration with photocatalytic oxidation

“…2c). And similar trendy was also found for the REs of other VOCs except Tol, which is likely due to the increase of relative humidity of waste gas after passing through the BTF reactor, resulting in lower adsorption capacity of VOCs than that of H 2 O on the photocatalyst surface [40,41], and then lower PCO REs. On the 30th day, it was worthwhile to point out that although the inlet concentrations of EA and Tol were 44 and 22 times higher than those of 15 days ago, the PCO REs increased from 77.6% to 96.9% and 86.6% to 96.2% for EA and Tol from the 15th day to 30th day.…”

Effect of key parameters on the photocatalytic oxidation of toluene at low concentrations in air under 254+185nm UV irradiation

“…Several studies suggested that photocatalysis using ozone-generating short-wavelength UV light [16][17][18][19][20] or in combination with atmospheric non-thermal plasma [21][22][23][24] can be suitable alternatives for indoor air cleaning. These radiation sources present the additional advantage of generating excess ozone, as well as other potentially harmful, reactive species that should be prevented from being introduced into occupied spaces.…”

Recent Development of VUV-Based Processes for Air Pollutant Degradation

“…VUV lamp has its main emission at 254 nm with a small (around 6%) intensity of irradiation at 185 nm, while UV lamp has its output only at 254 nm (Alapi and Dombi, 2007a). VUV photolysis is known for better performance on the removal of pollutants based on the following reasons: (1) the high-energy photons generated by 185 nm irradiation can degrade organic compounds; (2) in the presence of water, 185 nm irradiation can produce strong oxidants such as hydroxyl radical (•OH); (3) 185 nm irradiation can generate ozone in the presence of O 2 (Yang et al, 2007). Oxygen species [for example, O( 1 D), O( 3 P), and O 3 ] and hydroxyl radicals (•OH) are generated by the dissociation of oxygen and water molecules under VUV with high-energy photon according to the following reactions (Bergonzo and Boyd, 1993;Hashem et al, 1997;Equations 21-25):…”

“…More importantly, VUV photolysis will generate much toxic O 3 (Alapi and Dombi, 2007b;Yang et al, 2007), which is harmful to human health as it causes headaches, throat dryness and damage to mucus membranes at levels as low as 0.1-1 ppm . Thus, the residual O 3 will cause secondary pollution if not removed before emission.…”

“…Yang (Yang et al, 2007), Huang , and Jiang (Jiang et al, 2015) have tried to eliminate the air pollutants with VUV photolysis. Compared with UV, VUV can degrade air pollutants more efficiently due to the following reasons: (1) VUV can directly destruct the compounds due to its energetic photons; (2) With certain humidity, VUV irradiation can interact with water vapor and produce hydroxyl radicals that can degrade compounds; (3) Oxygen species like O( 1 D), O( 3 P), and O 3 can be formed from the reaction between VUV irradiation and oxygen (Bergonzo and Boyd, 1993;Hashem et al, 1997;.…”