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Oxidation kinetics of two pesticides in natural waters by ozonation and ozone combined with hydrogen peroxide.

Authors :
Chelme-Ayala P
El-Din MG
Smith DW
Adams CD
Source :
Water research [Water Res] 2011 Apr; Vol. 45 (8), pp. 2517-26. Date of Electronic Publication: 2011 Feb 12.
Publication Year :
2011

Abstract

The oxidation of bromoxynil and trifluralin was investigated using ozone (O(3)) and O(3) combined with hydrogen peroxide (H(2)O(2)) in natural waters using batch reactors. The results indicated that these pesticides could not be completely degraded during ozonation, achieving degradation levels lower than 50%. An enhancement of the level of degradation was observed using O(3)/H(2)O(2) process. A biphasic behaviour of O(3) was also observed. Depending on the experimental conditions, the rate constant for O(3) decomposition was estimated to be between 7.4 × 10(-4) s(-1) to 5.8 × 10(-2) s(-1), and 3.2 × 10(-3) s(-1) to 4.2 × 10(-2) s(-1) for bromoxynil and trifluralin samples, respectively. Acute toxicity analysis performed using Microtox(®) showed a decrease in the toxic effects of the samples on the luminescent bacteria during the first few minutes of treatment, followed by an increase of the toxic effects at the end of the reaction for both pesticides. The quantification of oxidation by-products generated during treatment was also addressed. The total molar balances of the degradation by-products versus the initial pesticide concentrations ranged from 60 to 103% under different experimental conditions.<br /> (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Details

Language :
English
ISSN :
1879-2448
Volume :
45
Issue :
8
Database :
MEDLINE
Journal :
Water research
Publication Type :
Academic Journal
Accession number :
21388652
Full Text :
https://doi.org/10.1016/j.watres.2011.02.007