Identification of intermediates and assessment of ecotoxicity in the oxidation products generated during the ozonation of clofibric acid

Rosal, R. and Gonzalo, S. and Boltes, K. and Letón, P. and Vaquero, J.J. and García-Calvo, E. (2009) Identification of intermediates and assessment of ecotoxicity in the oxidation products generated during the ozonation of clofibric acid. Journal of Hazardous Materials, 172 (2-3). pp. 1061-1068. ISSN 03043894

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Official URL: http://dx.doi.org/10.1016/j.jhazmat.2009.07.110

Abstract

The degradation of an aqueous solution of clofibric acid was investigated during catalytic and non-catalytic ozonation. The catalyst, TiO2, enhanced the production of hydroxyl radicals from ozone and raised the fraction or clofibric acid degraded by hydroxyl radicals. The rate constant for the reaction of clofibric acid and hydroxyl radicals was not affected by the presence of the catalyst. The toxicity of the oxidation products obtained during the reaction was assessed by means of Vibrio fischeri and Daphnia magna tests in order to evaluate the potential formation of toxic by-products. The results showed that the ozonation was enhanced by the presence of TiO2, the clofibric acid being removed completely after 15 min at pH 5. The evolution of dissolved organic carbon, specific ultraviolet absorption at 254 nm and the concentration of carboxylic acids monitored the degradation process. The formation of 4-chlorophenol, hydroquinone, 4-chlorocatechol, 2-hydroxyisobutyric acid and three non-aromatic compounds identified as a product of the ring-opening reaction was assessed by exact mass measurements performed by liquid chromatography coupled to time-of-flight mass spectrometry (LC-TOF-MS). The bioassays showed a significant increase in toxicity during the initial stages of ozonation following a toxicity pattern closely related to the formation of ring-opening by-products.

Item Type: Article
Uncontrolled Keywords: Ozonation; Toxicity; Kinetics; Titanium dioxide; Clofibric acid; D. magna; V. fischeri
Subjects: T Technology > TD Environmental technology. Sanitary engineering
T Technology > TP Chemical technology
Depositing User: José Ángel Gómez Martín
Date Deposited: 05 Jun 2013 14:47
Last Modified: 05 Jun 2013 14:47
URI: http://eprints.imdea-agua.org:13000/id/eprint/264

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