Photocatalytic Reductive Destruction of Azo Dyes by Polyoxometalates
-
A. Troupis
Abstract
Τhe polyoxometalate anions (POM) PW12O403- and SiW12O404- are proposed as efficient photocatalysts for the reductive degradation of the azo dyes Acid Orange 7 (AO), Naphthol Blue Black (NB) and Disperse Blue 79 in aqueous or ethanol solutions. The process involves absorption of light by polyoxometalates, oxidation of an organic sacrificial electron donor, for instance propan-2-ol or ethanol, and the subsequent reductive destruction of the azo dye by reduced POM with the concomitant recycling of the POM catalyst to the oxidized form. Preliminary results show that the dyes are reduced to aromatic amine derivatives. Increase of catalyst and/or propan-2-ol concentration accelerates the photodegradation of the dyes until a saturation value, while an optimum concentration of the added dye is usually required, due to an inner filter effect. The kind of POM catalyst dictates the efficiency of dye decoloration, following the order PW12O403- > SiW12O404- in one-pot photolysis experiments ((dye/propan-2-ol or ethanol/POM). The POM that is more efficient in photooxidizing the organic electron donor is also more efficient in reducing the azo dye due to the greater amounts of reduced catalyst that are formed. The presence of electron scavengers suppresses the degradation rate of dyes according to the trend Cu2+> O2 > Ni2+.
© 2016 by Walter de Gruyter Berlin/Boston
Artikel in diesem Heft
- Preface (TiO2-11 Section)
- Preface (AOTs-12 Section)
- Photocatalytic Decomposition of Formaldehyde Using Titania Coated Lime Tile
- TiO2-Nitrogen Modified for Water Decolourisation under VIS Radiation
- FTIR Studies of the Surface of TiO2, Fe-TiO2 and Fe-C-TiO2 Photocatalysts in Phenol Oxidation Via the Photo-Fenton Process
- Using Titania Photocatalysts to Degrade Toluene in a Combined Adsorption and Photocatalysis Process
- Photoelectrochemical Decomposition of VOCs on an Anodized TiO2 Plate
- Enhancement and Modeling of the Photocatalytic Degradation of Benzoic Acid
- Reactivity Indices for ortho/para Monosubstituted Phenols
- Modeling of the Photocatalytic Degradation Reactions of Aromatic Pollutants: A Solvent Effect Model
- Photodegradation of Malachite Green Using Immobilized TiO2 and Factorial Design
- Adsorption and Photodegradation of Humic Acids by Nano-Structured TiO2 for Water Treatment
- Photocatalytic Reductive Destruction of Azo Dyes by Polyoxometalates
- Effect of the Sintering Temperature on the Photocatalytic Activity of CdO + CdTiO3 Thin Films
- Photocatalytic Activity in Zn2TiO4 + ZnO Thin Films Obtained by the Sol-gel Process
- TiO2-Based Materials for Toluene Photocalytic Oxidation: Water Vapor Influence
- Influence of Aqueous Solubility of Various VOCs on Their Photocatalytic Degradation
- Photocatalysis: A Powerful Technology for Cold Storage Applications
- Some Remarks on So-Called Heterogeneous Photocatalysis and on the Mechanical Application of the Langmuir-Hinshelwood Kinetic Model
Artikel in diesem Heft
- Preface (TiO2-11 Section)
- Preface (AOTs-12 Section)
- Photocatalytic Decomposition of Formaldehyde Using Titania Coated Lime Tile
- TiO2-Nitrogen Modified for Water Decolourisation under VIS Radiation
- FTIR Studies of the Surface of TiO2, Fe-TiO2 and Fe-C-TiO2 Photocatalysts in Phenol Oxidation Via the Photo-Fenton Process
- Using Titania Photocatalysts to Degrade Toluene in a Combined Adsorption and Photocatalysis Process
- Photoelectrochemical Decomposition of VOCs on an Anodized TiO2 Plate
- Enhancement and Modeling of the Photocatalytic Degradation of Benzoic Acid
- Reactivity Indices for ortho/para Monosubstituted Phenols
- Modeling of the Photocatalytic Degradation Reactions of Aromatic Pollutants: A Solvent Effect Model
- Photodegradation of Malachite Green Using Immobilized TiO2 and Factorial Design
- Adsorption and Photodegradation of Humic Acids by Nano-Structured TiO2 for Water Treatment
- Photocatalytic Reductive Destruction of Azo Dyes by Polyoxometalates
- Effect of the Sintering Temperature on the Photocatalytic Activity of CdO + CdTiO3 Thin Films
- Photocatalytic Activity in Zn2TiO4 + ZnO Thin Films Obtained by the Sol-gel Process
- TiO2-Based Materials for Toluene Photocalytic Oxidation: Water Vapor Influence
- Influence of Aqueous Solubility of Various VOCs on Their Photocatalytic Degradation
- Photocatalysis: A Powerful Technology for Cold Storage Applications
- Some Remarks on So-Called Heterogeneous Photocatalysis and on the Mechanical Application of the Langmuir-Hinshelwood Kinetic Model
