title: UV light photo-Fenton degradation of polyphenols in oolong tea manufacturing wastewater.
abstract: The UV light photo-Fenton degradation of oolong tea polyphenols in tea manufacturing effluent that color the wastewater to a dark brown has been examined. In order to elucidate the photo-Fenton degradation mechanism of oolong tea polyphenols and find the optimal dosages of the Fenton reagents, systematic study has been conducted. For the UV light photo-Fenton degradation of oolong tea effluent being 70 mg-(polyphenol) L(-1), the optimum dosages of Fenton reagents were found to be 20 mgL(-1) of total Fe and 500 mgL(-1) of H2O2. The polyphenol degradation could be divided into two stages. The polyphenols concentration rapidly decreased to around 30% of the initial concentration within 2 min and the degradation rate significantly slowed down in the subsequent stage. After 60 min of UV light irradiation, 97% polyphenol removal was obtained. The initial quick degradation of oolong tea polyphenols suggests that hydroxyl radical generated by the photo-Fenton process might preferentially attack polyphenols having high antioxidant activity by scavenging hydroxyl radicals. Almost complete decolorization of the oolong tea effluent was achieved after 80 min. About 96% mineralization of 63 mgL(-1) TOC loading was achieved within 60 min and then further mineralization was rather slow. The complete COD removal of 239 mgL(-1) COD loading was obtained after 100 min. The present results indicate that the UV light photo-Fenton degradation process can treat tea manufacturing wastewaters very effectively.
authors.affiliation: a Research Center for Biochemical and Environmental Engineering, Department of Applied Chemistry , Toyo University , Kawagoe , Saitama , Japan.
authors.forename: Waraluk
authors.initials: W
authors.lastname: Sabaikai
authors.forename: Makoto
authors.initials: M
authors.lastname: Sekine
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tokumura
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kawase
mesh_terms: D006861:Hydrogen Peroxide / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D010084:Oxidation-Reduction; D059808:Polyphenols / Q000737:chemistry*; D013662:Tea / Q000737:chemistry*; D014466:Ultraviolet Rays; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: C045076:Fenton's reagent; D059808:Polyphenols; D013662:Tea; D014874:Water Pollutants, Chemical; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide; D007501:Iron