Indoor air purificaton using heterogeneous photocatalytic oxidation, Part 2: Kinetic study

In part I to this article [1], the application of the heterogeneous photocatalytic oxidation (PCO) theory for the indoor air quality improvement was presented. With a modified TiO2 that can be activated by visible light as the photocatalyst coated on a special wall paper, and one typical indoor air pollutant nitric oxide (NO) as model pollutant, the PCO experiments were performed in indoor air conditions and results show its effectiveness as an indoor air purifying technology. As the second part of the above mentioned study, this article addresses the kinetics of the photocatalytic oxidation of NO. A kinetic reaction rate model is proposed to describe the PCO of NO under indoor air conditions. The influence of the indoor air conditions such as pollutant concentration, volumetric flow rate of the pollutant, relative humidity, irradiance, dosage of the photocatalyst, and reactor size is considered in this model. As an undesired intermediate product in the process of the PCO of NO nitrogen dioxide (NO2) is incorporated as well from its influence on the PCO process. The good agreement between the predictions from this model and the experimental results indicates the validity of the proposed kinetic model.