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Web URL(s): | http://www.tandfonline.com/doi/pdf/10.1081/PFC-120035925 Last checked: 10/09/2015 Requires: PDF Reader Access conditions: Item is within a limited-access website |
Publication Type:
| Report |
Author(s): | Benitez, F. Javier;
Acero, Juan L.;
Real, Francisco J.;
Roman, Silvia |
Author Affiliation: | Departamento de Ingeniería Química y Energética, Universidad de Extremadura, Badajoz, Spain |
Title: | Oxidation of MCPA and 2,4-D by UV radiation, ozone, and the combinations UV/H2O2 and O3/H2O2 |
Source: | Journal of Environmental Science and Health: Part B: Pesticides, Food Contaminants, and Agricultural Wastes. Vol. B39, No. 3, May 2004, p. 393-409. |
Publishing Information: | New York: Marcel Dekker |
# of Pages: | 17 |
Keywords: | TIC Keywords: Oxidation; MCPA; 2,4-D; Radiation; Ozone; Pesticide degradation; Pesticide fate
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Abstract/Contents: | "The phenoxyalkyl acid derivative herbicides MCPA (4-chloro 2-methylphenoxyacetic acid) and 2,4-D (2,4-dichlorophenoxyacetic acid) were oxidized in ultrapure water by means of a monochromatic UV irradiation and by ozone, as well as by the combinations UV/H2O2 and O3/H2O2. In the direct photolysis of MCPA, the quantum yield at 20°C was directly evaluated and a value of 0.150 mol Eins-1 was obtained in the pH range 5-9, while a lower value of 0.41 × 10-2 mol Eins-1 was determined at pH = 3. Similarly, for 2,4-D a value of 0.81 × 10-2 mol Eins-1 was deduced, independent of the pH of work. The influence of the additional presence of hydrogen peroxide was established in the combined process UV/H2O2, and the specific contribution of the radical pathway to the global photo-degradation was evaluated. The oxidation by ozone and by the combination O3/H2O2 was also studied, with the determination of the rate constants for the reactions of both herbicides with ozone and hydroxyl radicals at 20°C. These rate constants for the direct reactions with ozone were 47.7 and 21.9 M-1s-1 for MCPA and 2,4-D respectively, while the found values for the rate constants corresponding to the radical reactions were 6.6 × 109 and 5.1 × 109M-1s-1." |
Language: | English |
References: | 27 |
See Also: | Other items relating to: 2, 4 - D in Turf |
Note: | Figures Tables Graphs |
| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete): Benitez, F. J., J. L. Acero, F. J. Real, and S. Roman. 2004. Oxidation of MCPA and 2,4-D by UV radiation, ozone, and the combinations UV/H2O2 and O3/H2O2. J. Environ. Sci. Health. B39(3):p. 393-409. |
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| Web URL(s): http://www.tandfonline.com/doi/pdf/10.1081/PFC-120035925 Last checked: 10/09/2015 Requires: PDF Reader Access conditions: Item is within a limited-access website |
| MSU catalog number: QH 545 .P4 J6 |
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