Document Detail


Identification of intermediates and assessment of ecotoxicity in the oxidation products generated during the ozonation of clofibric acid.
MedLine Citation:
PMID:  19709806     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The degradation of an aqueous solution of clofibric acid was investigated during catalytic and non-catalytic ozonation. The catalyst, TiO(2), 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 TiO(2,) 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.
Authors:
Roberto Rosal; Mar?a S Gonzalo; Karina Boltes; Pedro Let?n; Juan J Vaquero; E Garc?a-Calvo
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-08-04
Journal Detail:
Title:  Journal of hazardous materials     Volume:  172     ISSN:  1873-3336     ISO Abbreviation:  J. Hazard. Mater.     Publication Date:  2009 Dec 
Date Detail:
Created Date:  2009-11-02     Completed Date:  2010-02-09     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9422688     Medline TA:  J Hazard Mater     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  1061-8     Citation Subset:  IM    
Affiliation:
Departamento de Qu?mica Anal?tica e Ingenier?a Qu?mica, Universidad de Alcal?, E-28771 Alcal? de Henares, Spain. roberto.rosal@uah.es
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MeSH Terms
Descriptor/Qualifier:
Catalysis
Chromatography, Liquid
Clofibric Acid / chemistry*
Ecotoxicology / methods*
Hydrocarbons, Aromatic / analysis,  chemistry
Hydroxyl Radical / chemistry
Mass Spectrometry
Ozone / chemistry*
Titanium
Toxicity Tests
Chemical
Reg. No./Substance:
0/Hydrocarbons, Aromatic; 10028-15-6/Ozone; 13463-67-7/titanium dioxide; 3352-57-6/Hydroxyl Radical; 7440-32-6/Titanium; 882-09-7/Clofibric Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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