Photocatalytic air purification of polycyclic aromatic hydrocarbons: Application of a flow-through reactor, kinetic studies and degradation pathways

This study investigates the performance of a newly developed flow-through reactor and the utilized photocatalytic materials in two environments: a lab-scale experiment and a pilot-scale experiment in a contaminated building. The aim was to assess the removal of polycyclic aromatic hydrocarbons from the air using an innovative reactor equipped with an ultraviolet-irradiated titanium dioxide catalyst. Empirical measurements were conducted in the laboratory to revise the developed fixated titanium dioxide catalysts at different irradiances. Naphthalene and 1-methylnaphthalene elimination were used as model substances due to being the most volatile polycyclic aromatic hydrocarbons (PAH). In addition, they are often found in contaminated buildings. Tests in an office building revealed high suitability of the air cleaning system for low polycyclic aromatic hydrocarbons concentrations with a degradation of the compounds below the allowed limits of indoor air pollutants set by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety. The degradation of the organic micropollutants proceeded without detection of by-products, so that mineralization can be assumed. Based on these observations and a large number of previous studies, detailed degradation pathways for the selected micropollutants were also established.