title: Efficiency of hydroxyl radical formation and phenol decomposition using UV light emitting diodes and H2O2.
abstract: A novel process combining hydrogen peroxide (H2O2) and radiation emitted by ultraviolet light emitting diodes (UV LEDs) has been investigated. The UV LEDs were used as UV-C light sources emitting radiation in the range 257-277 nm for decomposition of the model substance phenol in water. In addition, the effect of H2O2 to phenol molar ratio and initial phenol concentration was examined. Two parameters, the decomposition efficiency of phenol and characterization of hydroxyl radical (HO*) production from H2O2 when illuminated with UV radiation, were selected to provide detailed information regarding the performance of the UV LEDs in the treatment process. A new concept was introduced to characterize and describe the production of HO* radicals produced when photons were absorbed by H2O2 molecules. The phenol decomposition efficiency at the initial concentration of 100 mg/L was the most pronounced at the lowest emitted wavelength. A significant correlation was found between the phenol decomposition efficiency and the photons absorbed by H2O2 (i.e. formation of radicals).
authors: Laboratory of Applied Environmental Chemistry, Faculty of Science and Forestry, University of Eastern Finland, Patteristonkatu 1, FI-50190 Mikkeli, Finland. sari.vilhunen@uef.fi
authors: Sari
authors: S
authors: Vilhunen
authors: Jarosław
authors: J
authors: Puton
authors: Jurate
authors: J
authors: Virkutyte
authors: Mika
authors: M
authors: Sillanpää
mesh_terms: D004867:Equipment Design; D006861:Hydrogen Peroxide / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000138:chemical synthesis / Q000528:radiation effects; D008029:Lighting / Q000295:instrumentation; D010636:Phenols / Q000737:chemistry* / Q000528:radiation effects*; D011829:Radiation Dosage; D012666:Semiconductors; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000528:radiation effects*; D018508:Water Purification / Q000379:methods*
chemical_list: D010636:Phenols; D014874:Water Pollutants, Chemical; D014867:Water; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide