Effects of microwave, UV, and O3 on propylene gas degradation via photocatalytic reaction with CVD TiO2 films

A microwave/UV/ozone/TiO2 photocatalyst hybrid process system, which is a combination of various propylene gas treatment techniques, is evaluated for use as an advanced, efficient technology for air pollution treatment. TiO2 photocatalyst balls were prepared using low-pressure metal-organic chemical vapor deposition. The microwave/UV/TiO2 photocatalyst hybrid process exhibited the higher degradation efficiency than the microwave/UV/alumina ball hybrid system. The degradation efficiency increased almost linearly with increasing ozone dose. The lower the propylene inlet concentration was the higher degradation efficiency. The double bond of propylene is broken by ozone and OH, resulting in production of CH4 and C2H6. These two intermediate products are mineralized into CO2, H2O, and CO. C2H4 and C3H8 may be produced from CH4, whereas C2H6 and C3H6 are produced by microwave irradiation.