PCDD/F formation in flaming combustion, smoldering, and oxidative pyrolysis of ‘eco-friendly’ treated wood

Tame, Nigel W.; Dlugogorski, Bogdan Z.; Kennedy, Eric M.

doi:10.1016/j.proci.2004.08.008

Cited by 21 publications

(13 citation statements)

References 21 publications

(26 reference statements)

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“…The present authors have demonstrated that combustion of treated wood in fires and in smallscale burners (e.g., heating barrels, combustion ovens) may lead to particularly high levels of PCDD/F both in ash and in gaseous emissions [1][2][3][4]. We have reported that the oxidative pyrolysis of wood treated with copper boron azole (CBA) could produce PCDD/F emissions as high as 7500 pg WHO 98 -TEQ/Nm 3 [2]. Timber treated with preservatives containing metals promoting char smouldering (such as CBA, ammoniacal copper quaternary, or chromated copper arsenate) may yield levels of PCDD/F of even 78 ng TEQ/kg ash, via the so-called de novo mechanisms, in comparison to 0.05 ng TEQ/kg ash from fires of untreated Pinus radiata [1].…”

Section: Introductionmentioning

confidence: 78%

“…Copper is a particularly potent catalyst for the formation of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofurans (PCDD/F). The present authors have demonstrated that combustion of treated wood in fires and in smallscale burners (e.g., heating barrels, combustion ovens) may lead to particularly high levels of PCDD/F both in ash and in gaseous emissions [1][2][3][4]. We have reported that the oxidative pyrolysis of wood treated with copper boron azole (CBA) could produce PCDD/F emissions as high as 7500 pg WHO 98 -TEQ/Nm 3 [2].…”

Section: Introductionmentioning

confidence: 96%

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PCDD/F Formation from Heterogeneous Oxidation of Wood Pyrolysates

Tame¹,

Dlugogorski²,

Kennedy³

2008

Fire Saf. Sci.

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This paper examines the formation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) during oxidative pyrolysis of wood. Model lignocellulosic compounds and fractions isolated from wood serve to generate volatiles which then interact with copper-loaded surrogate ash to produce PCDD/F. The measurements indicate a preference for the formation of PCDF over PCDD in all experiments. Lignin yields considerably more PCDD/F than the carbohydrates, in agreement with the previous measurement in experiments performed under inert conditions [Tame, Dlugogorski, Kennedy, Conversion of Wood Pyrolysates to PCDD/F, Proc. Combust. Inst. 32, submitted]. The ratio of PCDD to PCDF varies according to the chemical structure of the feed; with carbohydrates demonstrating greater relative propensity for PCDF than lignin. The lignin monomers with methyl ether subsitituents (i.e., vanillin and syringol) produce less PCDD/F than those without (i.e., catechol and p-hydroxybenzaldehyde). Ensuing experiments, to examine yield of PCDD/F as a function of temperature and mass loading of vanillin, reveal the mechanism of heterogeneous condensation of chlorophenols with subsequent chlorination/dechlorination.

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Section: Introductionmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 96%

PCDD/F Formation from Heterogeneous Oxidation of Wood Pyrolysates

Tame¹,

Dlugogorski²,

Kennedy³

2008

Fire Saf. Sci.

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“…The method for preparing the char sample from the original wood has been described in detail elsewhere [16,19]. Briefly, as-received timber lengths were shredded and dried in an inert atmosphere.…”

Section: Methodsmentioning

confidence: 99%

“…Therefore it is of considerable importance to relate the chemistry of timber fires to the mechanisms of dioxin formation, and ascertain the role of organic and inorganic contaminants common in waste-wood streams. Resins, plastics and pesticides could contribute to dioxin formation in wood fires [17][18][19] by supplying precursor molecules, additional chlorine sources and metal catalysts. The external addition of chlorine to wood is of particular importance as natural wood otherwise contains very low levels, which limits the PCDD/F-formation potential.…”

Section: Introductionmentioning

confidence: 99%

Formation Of Dioxin During Smoldering Of Cca Treated Wood Char

Tame¹,

Kennedy²,

Dlugogorski³

2005

Fire Safety Science - Proceedings of the Eigth International Sy

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Production of dioxin during the smoldering of wood char containing chromated copper arsenate (CCA) was investigated. Preliminary results are presented for the smoldering of treated wood char at 300 and 400°C, as a function of char loading, smoldering time and inlet oxygen concentrations. PCDF (mainly Cl 4 DF) were the preferred products of smoldering, and the results indicate the dependence of PCDD/F yields on competing formation/dechlorination reactions. Early periods of mass conversion favored PCDD/F formation, but with increasing mass loss, dechlorination and decomposition began to dominate. While the amounts detected were not particularly high (maximum yield of 95 ng TEQ/kg char oxidized), PCDD/F formation in wood fires may drastically increase with CCA combined with inorganic and organic chlorine contaminants.

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“…In general, the pyrethroids have been developed synthetically from the naturally occurring compound pyrethrum to preserve the toxicity of the natural species and to enhance their stability in sunlight. Their recent increase in popularity can be attributed to their effectiveness and potency in combating Lyctine borers and termites at low concentrations [1][2][3]. Alpha-cypermethrin is a highly active broad-spectrum insecticide, effective by contact and ingestion against target pests.…”

Section: Introductionmentioning

confidence: 99%

Formation of Polychlorinated Dibenzo-p-Dioxins and Polychlorinated Dibenzofurans and Their Precursors in Fires of Pyrethroid Pesticide Alpha-Cypermethrin

Summoogum¹,

Wojtalewicz²,

Mackie³

et al. 2011

Fire Safety Science - Proceedings of the 10th International Sym

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This study reports the results of the gas phase oxidation of alpha-cypermethrin, a common insecticide, elucidating the decomposition pathways and formation of toxic species such as polychlorinated dibenzo-pdioxins and polychlorinated dibenzofurans (PCDD/F) and their precursors. Conditions investigated are similar to those encountered in post combustion and cooling-down zones of forest, agricultural and wild fires, as well as in burning of biomass contaminated or treated with pesticides. The experiments were conducted under fuel lean conditions in a tubular reactor housed in a three-zone heating furnace and operated with a dilute stream of alpha-cypermethrin in ultra high purity nitrogen and oxygen. PCDD/F were identified and quantified by high resolution gas chromatography (HRGC)-ion trap mass spectrometry (ITMS). We detected mono to hepta chlorinated dibenzo-p-dioxins and dibenzofurans with maximum emission factors of 141 μg g of alpha-cypermethrin. 1-monochlorodibenzofuran was ranked as the most abundant congener. We also conducted the analyses of volatile organic compounds (VOC) attempting to identify the PCDD/F precursors by means of HRGCquadrupole mass spectrometry (QMS). The results of VOC revealed chlorobenzene, diphenyl ether, benzaldehyde, chlorotoluene, dichlorotoluene as important PCDD/F precursors.

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PCDD/F formation in flaming combustion, smoldering, and oxidative pyrolysis of ‘eco-friendly’ treated wood

Cited by 21 publications

References 21 publications

PCDD/F Formation from Heterogeneous Oxidation of Wood Pyrolysates

PCDD/F Formation from Heterogeneous Oxidation of Wood Pyrolysates

Formation Of Dioxin During Smoldering Of Cca Treated Wood Char

Formation of Polychlorinated Dibenzo-p-Dioxins and Polychlorinated Dibenzofurans and Their Precursors in Fires of Pyrethroid Pesticide Alpha-Cypermethrin

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