Ozone Catalytic Oxidation of Gaseous Toluene over MnO_2-Based Ozone Decomposition Catalysts Immobilized on a Nonwoven Fabric

Degradation of toluene gas by ozone catalytic oxidation (OZCO) by using a MnO_2-based ozone decomposition catalyst (ODC) was investigated to clarify the reactive site of ODC material with O_3. An optimum structure for the ODC to remove O_3 and toluene were proposed. For honeycomb ODC, toluene degradation by OZCO occurred only around the entrance of the honeycomb ODC, and we expected that a thinner ODC would increase the toluene degradation efficiency. A nonwoven fabric on which ODC was immobilized was developed to decompose O_3 and volatile organic compounds simultaneously. The toluene degradation ratio and the mineralization of toluene to CO_2 were determined to evaluate the performance of the fabric. Furthermore, the effects of relative humidity and O_3 concentration on the decomposition and mineralization ratios were also investigated with or without 254 nm UV irradiation (UV_(254)). The fabric decomposed and mineralized toluene to CO_2, even at low O_3 concentrations. Although high humidity reduced the degradation ratio of toluene, UV_(254) irradiation improved the recovery of the degradation ratio and increased the mineralization ratio.