title: Photocatalytic oxidation of methyl-orange in aqueous suspension: comparison of the performance of different polycrystalline titanium dioxide.
abstract: The photocatalytic oxidation of methyl-orange (C14H14N3SO3Na) dye was carried out in aqueous suspensions of polycrystalline TiO2 irradiated with artificial light until its complete mineralization was achieved. The performances of two widely used semiconductor powders were studied for comparison purposes. The dependence of dye photo-oxidation rate on various experimental parameters, including substrate concentration, semiconductor amount, and pH was investigated by using both catalysts. The observed dye degradation rates followed pseudo-first order kinetics with respect to the substrate concentration under the experimental conditions used. The two investigated TiO2 powders (Degussa P25 and Merck) showed different photoactivities. TOC analyses confirmed the complete mineralization achievable using both photocatalysts. Three main transient products still maintaining the chromophoric azo group were identified prior to their transformation into other degradation products which are non-absorbing in the visible region.
authors.affiliation: Dipartimento di Ingegneria Chimica dei Processi e dei Materiali, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Marcì
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Augugliaro
authors.forename: Alessandra
authors.initials: A
authors.lastname: Bianco Prevot
authors.forename: Claudio
authors.initials: C
authors.lastname: Baiocchi
authors.forename: Elisa
authors.initials: E
authors.lastname: García-López
authors.forename: Vittorio
authors.initials: V
authors.lastname: Loddo
authors.forename: Leonardo
authors.initials: L
authors.lastname: Palmisano
authors.forename: Edmondo
authors.initials: E
authors.lastname: Pramauro
authors.forename: Mario
authors.initials: M
authors.lastname: Schiavello
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D002384:Catalysis; D004396:Coloring Agents / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010084:Oxidation-Reduction; D010782:Photolysis; D013535:Suspensions; D013783:Textile Industry / Q000379:methods; D014025:Titanium / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D013535:Suspensions; D014874:Water Pollutants, Chemical; D014867:Water; C009495:titanium dioxide; C100258:methyl orange; D014025:Titanium