Abstract
Photocatalytic technology was applied to reduce formaldehyde in the indoor environment. In photocatalytic reactions, there is a major technical problem regarding how to accelerate oxidative destruction reactions to minimize the generation of hazardous by products. Using photocatalytic units with UV lamps placed at both sides of TiO2 photocatalysts, we have attempted to improve the performance of decompositional removal. We performed an experiment to determine decompositional removal characteristics in the circulation treatment process of formaldehyde (approx. 100ppm) within a 1m3 closed air chamber. The result showed that the formaldehyde was almost completely oxidized into carbon dioxide when the intensity of UV light is over 2.9mW/cm2. The decompositional removal performance of formaldehyde was improved by either increasing the irradiation intensity, slowing down the surface air velocity on the photocatalytic filter, or installing photocatalytic units on a multistage basis. By installing three sets of the photocatalytic units, the generated formic acid upon the decomposition of formaldehyde was effectively caught by the unit of downstream, the installation of multistage of photocatalytic units is effective as a measure to suppress the release of formic acid.
