Heterogeneous oxidation of two triazole pesticides (diniconazole and tebuconazole) by OH-radicals and ozone.
Sci Total Environ
; 694: 133745, 2019 Dec 01.
Article
em En
| MEDLINE
| ID: mdl-31756792
ABSTRACT
Tebuconazole (Tbz) and diniconazole (Dnz) were deposited as thin film on quartz plaques. They were submitted to OH-radicals and ozone and their kinetic was measured. OH-radical oxidation was performed relative to a reference whose rate constant is well known. Terbuthylazine (Tbt) and Chlorpyriphos Ethyl (Clp) were chosen as reference for Tbz and Dnz kinetics determination, respectively. OH-radical rate constants of Tbz and Dnz were found to be kOH+Tbzâ¯=â¯(1.7⯱â¯0.2) 10-13â¯cm3â¯molecule-1â¯s-1 and k OH+Dnzâ¯=â¯(1.74⯱â¯1.21) 10-12â¯cm3â¯molecule-1â¯s-1, respectively. Ozone heterogeneous oxidation rate constants were determined in an absolute way kO3+Tbzâ¯=â¯(0.5⯱â¯0.2) 10-20â¯cm3â¯molecule-1â¯s-1; kO3+Dnzâ¯=â¯(1.4⯱â¯0.2) 10-19â¯cm3â¯molecule-1â¯s-1. Dnz is ten times more reactive toward OH-radicals than Tbz and 27 times more reactive than Tbz toward ozone maybe because of the presence of a double bond in Dnz. Lifetimes of Tbz and Dnz on quartz like surfaces are against OH-radicals are of 68â¯days and 8â¯days, respectively and 4â¯months and several years against ozone, respectively.
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Ano de publicação:
2019
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Article