6533b81ffe1ef96bd1276f55

RESEARCH PRODUCT

VOC's abatement: Photocatalytic oxidation of toluene in vapour phase on anatase TiO2 catalyst

subject

description

Publisher Summary The photocatalytic oxidation of toluene in the presence of water was performed in the gas–solid regime at room temperature by using TiO2. It has been found that the presence of water was beneficial to achieve the almost complete photo-oxidation of toluene to CO2 and H2O, in fact, only very small amounts of benzaldehyde vapor that is the main product of toluene partial oxidation, were detected. Volatile organic compounds, VOC's, are an important class of air pollutants usually found in the atmosphere of all urban and industrial areas. Toluene is one of these compounds, and because of its noxious nature several strategies have been identified to reduce its presence in indoor and industrial emissions. This chapter discusses the results of the toluene photo-oxidation reaction, using polycrystalline anatase TiO2, as catalyst. The photoreactivity runs were carried out in a continuous photoreactor fed by a mixture of air, toluene, and water in various molar ratios and irradiated in the near-UV region. Blank reactivity tests were performed at the same experimental conditions used for the photoreactivity experiments, but in the absence of catalyst, oxygen, or light. Other runs were carried out by using CO2 or N2 instead of O2. No reactivity was observed in all these cases so that it may be concluded that O2, catalyst, and irradiation are needed for the occurrence of the photo process. The photoreactivity results showed that the reactor reaches steady state conditions after a long period of time from the beginning of the irradiation. At steady state conditions, the main photo-oxidation product was not only benzaldehyde, but also benzyl alcohol and traces of benzoic acid and phenol were detected at all the experimental conditions used.