Mechanism of chlorination of aromatic compounds adsorbed on the surface of fly ash from municipal incinerators

Hoffman, Robert V.; Eiceman, Gary A.; Long, Yao; Collins, Mary; Lu, Mao

doi:10.1021/es00081a002

Cited by 71 publications

(42 citation statements)

References 8 publications

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“…A higher copper concentration was found in the SeCu fly ash used in this study (260 mg/g) than has been found in MWI fly ash (0.3-4.6 mg/g) (Cains et al 1997). The zinc concentration in the fly ash used in this study was 166 mg/g, which was also higher than has been found in MWI fly ash (0.7-30.6 mg/g) (Hoffman et al 1990). The presence of chlorine is also an important factor that affects the formation of PCDD/Fs (Wikström et al 2003).…”

Section: Quality Control and Assurancecontrasting

confidence: 53%

Formation and potential mechanisms of polychlorinated dibenzo-p-dioxins and dibenzofurans on fly ash from a secondary copper smelting process

Wang

Liu

Jiang

et al. 2015

Environ Sci Pollut Res

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Secondary copper smelting (SeCu) is widely considered to be an important source of polychlorinated dibenzop-dioxins and dibenzofurans (PCDDs and PCDFs; PCDD/Fs). Laboratory experiments were performed using SeCu fly ash as a matrix for thermochemical reactions to investigate the effects of fly ash on the formation of PCDD/Fs and the potential mechanisms. Thermochemical reactions on SeCu fly ash over a temperature range of 250-450°C and reaction times of 10-120 min caused the PCDD/F concentrations in the fly ash to increase significantly. The PCDD/F concentrations formed in the thermal reactions were about 99-139 times higher than the PCDD/F concentrations in the original fly ash, clearly indicating that fly ash promoted the formation of PCDD/Fs. The PCDFs dominated the PCDDs, and the PCDF/PCDD concentration ratio was about 30-40. Octachlorodibenzofuran ( O C D F ) , o c t a c h l o r o d i b e n z o -p -d i o x i n , a n d t h e heptachlorodibenzofurans were the most dominant homologs that were formed. A comparison of the PCDD/F patterns produced in the thermochemical reactions and the patterns in the original fly ash suggested that the chlorination of less chlorinated PCDFs might be an important pathway in the formation of higher chlorinated furans. The results of this study indicated that SeCu fly ash has a high PCDD/F formation potential. It is crucial to have the fly ash filter at low temperature and that fly ash in the cooling system should be minimized.

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Section: Quality Control and Assurancecontrasting

confidence: 53%

Formation and potential mechanisms of polychlorinated dibenzo-p-dioxins and dibenzofurans on fly ash from a secondary copper smelting process

Wang

Liu

Jiang

et al. 2015

Environ Sci Pollut Res

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“…It has been found in a number of studies that the chlorine content affects POPs concentrations and that chlorination is an important POPs formation pathway [30,38]. The chlorination of naphthalene and less-chlorinated PCNs could be catalyzed by metal chlorides, such as CuCl 2 and FeCl 3 [29,30,38].…”

Section: Variations and The Factors Influencing Pcn Concentrations Inmentioning

confidence: 99%

Variations and factors that influence the formation of polychlorinated naphthalenes in cement kilns co-processing solid waste

Jin

Zhan

Liu

et al. 2016

Journal of Hazardous Materials

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h i g h l i g h t s• PCN destruction efficiencies of cement kilns were derived.• Factors influencing PCN variation and formation were identified.• Major pathways for PCN formation and decomposition in cement kiln were discussed.• PCN indicators for sources involved with coal burning were proposed. a r t i c l e i n f o b s t r a c tPilot studies of unintentionally produced pollutants should be performed before waste being coprocessed in cement kilns. Polychlorinated naphthalene (PCN) formation and emission from cement kilns co-processing sorted municipal solid waste, sewage sludge, and waste acid, however, have not previously been studied. Here, PCNs were analyzed in stack gas samples and solid samples from different stages of three cement production runs. PCN destruction efficiencies were higher when waste was coprocessed (93.1% and 88.7% in two tests) than when waste was not co-processed (39.1%), so co-processing waste would not increase PCN outputs. The PCN concentrations were higher in particle samples from the C1 preheater and stages at back end of kiln than in particle samples from other stages, suggesting that cyclone preheater and back end of kiln should be focused for controlling PCN emissions. Besides that, based on the variation of PCN concentrations and corresponding operating conditions in different stages, the temperature, feeding materials, and chlorine content were suggested as the main factors influencing PCN formation. The PCN homologue and congener profiles suggested chlorination and dechlorination were the main PCN formation and decomposition pathways, and congeners CN-23, CN-46, and CN-59 appear to be appropriate indicators of PCNs emitted from coal-burning sources.

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“…We thought that dioxins were generated by a synergetic effect of proposed catalytic chlorination [18][19][20] by cupric and ferric chlorides, apart from for direct chlorination.…”

Section: Comparison Of Influences Among Heavy Metal Chloridesmentioning

confidence: 99%

Chlorination Mechanism of Carbon during Dioxin Formation Using Cl-K Near-edge X-ray-absorption Fine Structure

et al. 2010

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Many environmental organic chemicals have chloride in their structure. Thus, researching the chlorination mechanism of carbon is of interest. Dioxins are typically concentrated in fly ash collected from the post-combustion zone during the operation of municipal solid waste incinerators. In this study, we report the application of Cl-K near-edge X-rayabsorption fine structure (NEXAFS) in determining the chlorination mechanism of carbon in fly ash. The separation of a chloride-carbon (C-Cl) bond was readily recognizable as a peak in the Cl-K NEXAFS spectrum. Chlorination effects could be estimated using Cl K-edge NEXAFS with no dependence on metal species. Analysis of Cl K-edge NEXAFS spectra showed the reduction of copper(II) chloride at 300 C and oxidation of iron(III) chloride at 400 C in connection with the chlorination of carbon.

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Mechanism of chlorination of aromatic compounds adsorbed on the surface of fly ash from municipal incinerators

Cited by 71 publications

References 8 publications

Formation and potential mechanisms of polychlorinated dibenzo-p-dioxins and dibenzofurans on fly ash from a secondary copper smelting process

Formation and potential mechanisms of polychlorinated dibenzo-p-dioxins and dibenzofurans on fly ash from a secondary copper smelting process

Variations and factors that influence the formation of polychlorinated naphthalenes in cement kilns co-processing solid waste

Chlorination Mechanism of Carbon during Dioxin Formation Using Cl-K Near-edge X-ray-absorption Fine Structure

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