title: Different methods in TiO2 photodegradation mechanism studies: gaseous and TiO2-adsorbed phases.
abstract: The development of photocatalysis processes offers a significant number of perspectives especially in gaseous phase depollution. It is proved that the photo-oxidizing properties of photocatalyst (TiO(2)) activated by UV plays an important role in the degradation of volatile organic compounds (VOC). Heterogeneous photocatalysis is based on the absorption of UV radiations by TiO(2). This phenomenon leads to the degradation and the oxidation of the compounds, according to a mechanism that associates the pollutant's adsorption on the photocatalyst and radical degradation reactions. The main objective of the study is the understanding of the TiO(2)-photocatalysis phenomenon including gaseous and adsorbed phase mechanisms. Results obtained with three different apparatus are compared; gaseous phases are analysed and mechanisms at the gaseous phase/photocatalyst interface are identified. This study leads to improve understanding of various mechanisms during pollutant photodegradation: adsorption of pollutants on TiO(2) first takes place, then desorption and/or photodegradation, and finally, desorption of degradation products on TiO(2). The association of analytical methods and different processes makes the determination of all parameters that affect the photocatalytic process possible. Mastering these parameters is fundamental for the design and construction of industrial size reactors that aim to purify the atmosphere.
authors.affiliation: Groupe de Recherche sur l'Environnement et la Chimie Atmosphérique, Université Joseph Fourier Grenoble I, France.
authors.forename: Pierre-Alexandre
authors.initials: PA
authors.lastname: Deveau
authors.forename: Fabrice
authors.initials: F
authors.lastname: Arsac
authors.forename: Pierre-Xavier
authors.initials: PX
authors.lastname: Thivel
authors.forename: Corinne
authors.initials: C
authors.lastname: Ferronato
authors.forename: Françoise
authors.initials: F
authors.lastname: Delpech
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Chovelon
authors.forename: Pascal
authors.initials: P
authors.lastname: Kaluzny
authors.forename: Christine
authors.initials: C
authors.lastname: Monnet
mesh_terms: D000327:Adsorption; D000393:Air Pollutants / Q000737:chemistry* / Q000528:radiation effects; D000397:Air Pollution / Q000517:prevention & control*; D002384:Catalysis; D005740:Gases / Q000737:chemistry / Q000528:radiation effects; D010777:Photochemistry; D014025:Titanium / Q000737:chemistry*; D014050:Toluene / Q000737:chemistry* / Q000528:radiation effects; D014466:Ultraviolet Rays; D018505:Waste Management / Q000379:methods
chemical_list: D000393:Air Pollutants; D005740:Gases; C009495:titanium dioxide; D014050:Toluene; D014025:Titanium