Gas-phase atmospheric chemistry of dibenzo-p-dioxin and dibenzofuran

Kwok, Eric S. C.; Arey, Janet; Atkinson, Roger

doi:10.1021/es00052a028

Cited by 54 publications

(39 citation statements)

References 42 publications

(69 reference statements)

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“…Compared with other dioxin control technologies [16], the destruction efficiencies of dioxin-like compounds achieved with DBD plasma were relatively lower than those achieved with activated carbon adsorption or catalytic decomposition. The significantly lower destruction efficiency of dioxin-like PCBs achieved with DBD plasma may be attributed to the fact that PCBs were probably regenerated from the dechlorination of non-toxic congeners of highly chlorinated PCBs or the deoxygenation of PCDFs [28]. In a DBD reactor, UV, electrons (e − ), and free radicals (such as OH radicals) are generated and react with dioxin-like compounds.…”

Section: Discussionmentioning

confidence: 99%

Degradation of gaseous dioxin-like compounds with dielectric barrier discharges

Hung

Chang

Hsien

et al. 2010

Journal of Hazardous Materials

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Section: Discussionmentioning

confidence: 99%

Degradation of gaseous dioxin-like compounds with dielectric barrier discharges

Hung

Chang

Hsien

et al. 2010

Journal of Hazardous Materials

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“…More intense solar radiation and higher temperatures in summer can result in a greater photochemical reaction, which results in more gaseous PCDD loss in summer than in winter. The PCDFs are less chemically stable than PCDDs and thus may degrade more quickly, resulting in a higher photolysis rate in the particulate matter . However, we found a good linear relationship between 2378‐PCDFs and OC concentrations in summer.…”

Section: Resultsmentioning

confidence: 60%

Spatial and temporal variation, source profile, and formation mechanisms of PCDD/Fs in the atmosphere of an e‐waste recycling area, South China

Xiao

Chen

et al. 2014

Enviro Toxic and Chemistry

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The present study investigated the impact of typical electronic waste (e-waste) dismantling activities on the distribution of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the adjacent atmospheric environment. The target areas included the town of Longtang, a well known e-waste recycling site, and 2 affected neighborhoods, all of which were within the city of Qingyuan, Guangdong Province, China. Air samples were collected from the 3 locations and analyzed following the standard methods. The results showed that the atmospheric PCDD/F level in Longtang was 159.41 pg m À3 , which was approximately 16 to 17 times higher than its neighborhoods and 2 to 4 orders of magnitude higher than baseline levels reported for urban cities of the world. The homologue profiles were quite different from the typical urban air patterns, as de novo synthesis was likely to be the dominant formation pathway of the detected PCDD/Fs. The seasonal variations were minor, and the concentration change of PCDD/Fs between day and night did not follow a clear pattern. Given the unique atmospheric PCDD/F concentrations, similar homologue profiles, and the elemental carbon/organic carbon relationships of the 3 sampling sites, the relatively high dioxin levels in its 2 neighborhoods were most likely the result of the primitive e-waste dismantling activities undertaken in the town of Longtang. A simple risk assessment also showed that the residents of Qingyuan were at high risk of exposure to PCDD/Fs. Environ Toxicol Chem 2014;33:500-507. # 2013 SETAC

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“…13,15 It is well-known SCHEME 2: Mechanistic Diagram of the DF-OH(1) Reaction with Dioxygen where a negative temperature dependence has also been observed. The calculated rate constant is almost 20 times faster than that for benzene, 19,37 4 times faster than that of the toluene system, 38 only twice as fast as that of p-xylene, 23 and the same as that of phenol.…”

Section: Df-oh Adductsmentioning

confidence: 99%

Computational Study of the Oxidation and Decomposition of Dibenzofuran under Atmospheric Conditions

et al. 2008

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The atmospheric degradation of dibenzofuran (DF) initiated by OH addition has been studied by using density functional theory (B3LYP method). Site C1 in DF is predicted to be the favored site for OH addition, with a branching ratio of 0.61 to produce a DF-OH(1) adduct. The calculated reaction rate constant for OH addition to DF has been used to predict the atmospheric lifetime of DF to be 0.45 day. Three different modes of attack of O2 ((3)Sigma(g)) on DF-OH(1) have been examined. Abstraction of hydrogen gem to OH in DF-OH(1) by O2 ((3)Sigma(g)) (producing 1-dibenzofuranol I) and dioxygen addition in the three radical sites in cis and trans orientation (relative to the ispo-added OH) of the pi-delocalized electron system of DF-OH(1) are feasible under atmospheric conditions. The free energy of activation (at 298.15 K) for the formation of 1-dibenzofuranol is 15.1 kcal/mol with a free energy change of -36.3 kcal/mol, while the formation of DF-OH(1)-O2 adducts are endergonic by 9.2-21.8 kcal/mol with a 16.3-23.6 kcal/mol free energy of activation. On the basis of the calculated reaction rate constants, the formation of 1-dibenzofuranol is more important than the formation of DF-OH-O2 adducts. The results presented here are a first attempt to gain a better understanding of the atmospheric oxidation of dioxin-like compounds on a precise molecular basis.

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Gas-phase atmospheric chemistry of dibenzo-p-dioxin and dibenzofuran

Cited by 54 publications

References 42 publications

Degradation of gaseous dioxin-like compounds with dielectric barrier discharges

Degradation of gaseous dioxin-like compounds with dielectric barrier discharges

Spatial and temporal variation, source profile, and formation mechanisms of PCDD/Fs in the atmosphere of an e‐waste recycling area, South China

Computational Study of the Oxidation and Decomposition of Dibenzofuran under Atmospheric Conditions

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