- Title
- Formation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) by precursor pathways in oxidation of pesticide alpha-cypermethrin
- Creator
- Summoogum, Sindra L.; Wojtalewicz, Dominika; Altarawneh, Mohammednoor; Mackie, John C.; Kennedy, Eric M.; Dlugogorski, Bogdan Z.
- Relation
- ARC
- Relation
- Proceedings of the Combustion Institute Vol. 34, p. 3499-3507
- Publisher Link
- http://dx.doi.org/10.1016/j.proci.2012.06.020
- Publisher
- Elsevier
- Resource Type
- journal article
- Date
- 2013
- Description
- This contribution assesses the oxidation of the commonly used insecticide and termiticide, alpha-cypermethrin to polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F, dioxins) and their precursors, under non-catalytic vapour-phase oxidation, in a flow reactor. No soot was produced during the reaction ruling out the de novo synthesis of PCDD/F. The results span the effect of temperature (300–650 °C) and fuel equivalence ratio (φ of 0.01–7.0), at a residence time of 1 s. XAD-2 resin trapped the PCDD/F which were identified and quantitated by high resolution gas chromatography (HRGC)–ion trap mass spectrometry (ITMS). The reactor walls appear to have no noticeable effect on the initiation of the gas-phase oxidation reactions. The decomposition of alpha-cypermethrin produces two types of PCDD/F precursors, chlorinated benzenes (CBz)/chlorinated phenols (CP) and two-ring species, mainly diphenyl ether and chlorinated diphenyl ethers (CDPE). The CBz/CP precursors comprise chlorobenzene, o-, m- and p-dichlorobenzene, 1,2,3-trichlorobenzene, phenol, 2-monochlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP) and 2,4,6-TriCP, with minor amount of 2,4,5-TriCP. The highest emission factor for PCDD/F was observed at 550 °C and a fuel equivalence ratio of 0.03, corresponding to 19 ng ∑TEQ–WHO2005/g of alpha-cypermethrin and the total dioxins concentration of 141 μg/g of alpha-cypermethrin. These emissions are one of the highest measured from oxidation of presently used pesticides.
- Subject
- dioxins; fuel equivalence ratio; PCDD/F precursors; pesticide oxidation
- Identifier
- http://hdl.handle.net/1959.13/1300931
- Identifier
- uon:20190
- Identifier
- ISSN:1540-7489
- Language
- eng
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