Gas phase photocatalytic oxidation of VOC using TiO_2-containing paint: influence of NO and relative humidity

摘要

Advanced oxidation process (AOP) such as photocatalysis is a promising technology for air purification. It is the purpose of this study to investigate the photocatalytic removal of volatile organic compound (VOC) using TiO_2-containing paints. The photocatalytic activity of the paint was studied in a walk-in type environmental chamber (30 m~3) under a realistic level of irradiation, humidity and VOC amount with reference to a typical urban air pollutant concentration. The effects of concurrent photodegradation of NO and VOC as well as the effect of the relative humidity level were also investigated in order to evaluate the feasibility of the photocatalytic building material (paint) for air purification under real conditions. It was found that the presence of NO promoted the photodegradation of toluene, under low humidity levels (17% RH), up to 15%. It was suggested that the enhancement of toluene conversion was due to the generation of OH radicals during the photodegradation of NO. Results were also showed that no photodegradation of toluene was found while increasing humidity up to 50%.