Modeling of volatile organic compounds degradation by photocatalytic oxidation reactor in indoor air: A review

Photocatalytic oxidation (PCO) has a great potential to eliminate various gaseous pollutants even at low concentrations. Numerous studies have been carried out to improve the effectiveness and performance of this technology. In addition, the development of appropriate models can enhance the understanding of reactor performance and the evaluation the intrinsic kinetic parameters that enable the scale up or re-design of more efficient large-scale photocatalytic reactors. This paper reviews recent research works on mathematical modeling of gas phase photocatalytic reactors and analyses different key factors that can enhance pollutants decomposition performance. First, the fundamental of the photocatalytic oxidation process and degradation reaction mechanism are briefly described. Then, to study kinetics of reaction, this paper focuses on LangmuirHinshelwood equation, which is by far the most common kinetic model that takes both adsorption and reaction processes into account. Moreover, an overall mass balance that contains advection, diffusion, and reaction rate terms, is analyzed to obtain a comprehensive mathematical model. In the end, the influence of key operating parameters (e.g. flow rate, catalyst surface area and porosity, and catalyst thickness) on the photocatalytic process and removal efficiency of the reactor are discussed.