title: Advanced oxidation of the pharmaceutical drug diclofenac with UV/H2O2 and ozone.
abstract: Diclofenac, a widely used anti-inflammatory drug, has been found in many Sewage Treatment Plant effluents, rivers and lake waters, and has been reported to exhibit adverse effects on fish. Advanced oxidation processes, ozonation and H2O2/UV were investigated for its degradation in water. The kinetic of the degradation reaction and the nature of the intermediate products were still poorly defined. Under the conditions adopted in the present study, both ozonation and H2O2/UV systems proved to be effective in inducing diclofenac degradation, ensuring a complete conversion of the chlorine into chloride ions and degrees of mineralization of 32% for ozonation and 39% for H2O2/UV after a 90 min treatment. The reactions were found to follow similar, but not identical, reaction pathways leading to hydroxylated intermediates (e.g. 2-[(2,6-dichlorophenyl)amino]-5-hydroxyphenylacetic acid) and C-N cleavage products (notably 2,5-dihydroxyphenylacetic acid) through competitive routes. Subsequent oxidative ring cleavage leads to carboxylic acid fragments via classic degradation pathways. In the pH range 5.0-6.0 kinetic constants (1.76 x 10(4)-1.84 x 10(4) M(-1) s(-1)) were estimated for diclofenac ozonation.
authors.affiliation: Dip. di Chimica Organica e Biochimica, Federico II, Facolta di Scienze, Universita degli Studi di Napoli Complesso Universitario M. S. Angelo, via Cinthia, 4, 80126, Napoli, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Vogna
authors.forename: Raffaele
authors.initials: R
authors.lastname: Marotta
authors.forename: Alessandra
authors.initials: A
authors.lastname: Napolitano
authors.forename: Roberto
authors.initials: R
authors.lastname: Andreozzi
authors.forename: Marco
authors.initials: M
authors.lastname: d'Ischia
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry* / Q000302:isolation & purification; D004008:Diclofenac / Q000737:chemistry* / Q000302:isolation & purification; D006861:Hydrogen Peroxide / Q000737:chemistry*; D016877:Oxidants / Q000737:chemistry*; D010083:Oxidants, Photochemical / Q000737:chemistry*; D010084:Oxidation-Reduction; D010126:Ozone / Q000737:chemistry*; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000302:isolation & purification; D018508:Water Purification / Q000379:methods*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D016877:Oxidants; D010083:Oxidants, Photochemical; D014874:Water Pollutants, Chemical; D004008:Diclofenac; D010126:Ozone; D006861:Hydrogen Peroxide