Photocatalytic destruction of VOCs for in-vehicle air cleaning

摘要

In order to reduce vehicle occupants' exposures to aromatic volatile organic compounds (VOCs), it is necessary to develop control strategies for in-vehicle VOCs. This study evaluated the technical feasibility of the application of TiO_2 photocatalysis for the removal of VOCs present in air at low parts per billion (ppb) concentrations commonly associated with in-vehicle air quality issues. The photocatalytic removal of five target VOCs was investigated: benzene, ethyl benzene, and o-, m-, p-xylenes. Variables tested for the current study in clouded relative humidity (RH), hydraulic diameter (HD) and flow rate (FW). The fixed parameters included contaminant concentration, UV light source, photocatalytic oxidation (PCO) reactor material and the weight of TiO_2. Under the experimental conditions, the PCO destruction efficiencies were close to 100% for four different RH ranges that cover typical ambient air humidity ranges. The efficiency of PCO was dependent on the HD of the reactor and the stream FW. Some carbon monoxide was formed as a by-product in the oxidation albeit at low levels.