title: Highly concentrated phenolic wastewater treatment by the photo-Fenton reaction, mechanism study by FTIR-ATR.
abstract: Phenol degradation by Photo-Fenton reaction has been studied in highly concentrated wastewaters and most intermediate species have been identified by Fourier Transform IR-Spectroscopy with ATR device. During the photodegradation of highly concentrated phenol solutions, the formation of dissolved and precipitate tannin has been observed. The possibility of a Fe3+-Pyrogallol complex formation, previous to the tannin formation, has been proposed too. The complex formation involving Fe3+ ions could be related to the observed Photo-Fenton activity decrease. Tannin formation inhibits the complete mineralization of phenol because *OH radicals attack will produce further condensation steps and the polymer size increase. This fact limits the applicability of the process for highly concentrated phenolic wastes mineralization. However, the tannin precipitation allows its separation from the solution by conventional filtration, and reduction of the corresponding dissolved organic carbon. These observations have been proved from the identification of primary degradation products, catechol and hydroquinone. Catechol is considered to be the first step for the formation of tannins. Degradation process for phenol, catechol and hydroquinone have been monitored by total organic carbon (TOC) measurements along the reaction time span. From these results, a global mechanism for the Photo-Fenton degradation of phenol is proposed.
authors.affiliation: Departamento de Química, Universidad de Las Palmas de Gran Canaria, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Araña
authors.forename: E
authors.initials: E
authors.lastname: Tello Rendón
authors.forename: J M
authors.initials: JM
authors.lastname: Doña Rodríguez
authors.forename: J A
authors.initials: JA
authors.lastname: Herrera Melián
authors.forename: O
authors.initials: O
authors.lastname: González Díaz
authors.forename: J
authors.initials: J
authors.lastname: Pérez Peña
mesh_terms: D004784:Environmental Monitoring; D005609:Free Radicals; D006861:Hydrogen Peroxide / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D008903:Minerals; D010636:Phenols / Q000737:chemistry*; D010777:Photochemistry; D011108:Polymers; D017550:Spectroscopy, Fourier Transform Infrared; D014865:Waste Disposal, Fluid; D018508:Water Purification
chemical_list: C045076:Fenton's reagent; D005609:Free Radicals; D008903:Minerals; D010636:Phenols; D011108:Polymers; D006861:Hydrogen Peroxide; D007501:Iron