Highly concentrated phenolic wastewater treatment by heterogeneous and homogeneous photocatalysis: mechanism study by FTIR-ATR.
The degradation of high phenol concentrations (1 g/L) in water solutions by TiO2 photocatalysis and the photo-Fenton reaction has been studied. From the obtained data it may be suggested that degradation of phenol by TiO2-UV takes place onto the catalyst surface by means of peroxo-compounds formation. At low phenol concentrations other mechanism, the insertion of OH. radicals, may be favored. On the other hand, highly concentrated phenol aqueous solutions treatment by the photo-Fenton reaction gives rise to the formation of polyphenolic polymers. These seem to reduce the process rate. Degradation intermediates have been identified by HPLC and FTIR. The FTIR study of the catalyst surface has shown infrared bands attributable to different chemisorbed peroxo-compounds, formates, ortho-formates and carboxylates that can inactivate the catalyst.
Araña
J
J
Departamento de Química, Universidad de Las Palmas de Gran Canaria, España.
Tello-Rendón
E
E
Doña-Rodríguez
J M
JM
Campo
C V
CV
Herrera-Melidán
J A
JA
González-Díaz
Pérez-Peña
J
J
D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D004396:Coloring Agents / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry*; D010777:Photochemistry; D017550:Spectroscopy, Fourier Transform Infrared; D014025:Titanium / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*
D004396:Coloring Agents; C045076:Fenton's reagent; D010636:Phenols; C009495:titanium dioxide; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide; D014025:Titanium; D007501:Iron