Thermodynamic study on the reduction of the polychlorinated dibenzo-p-dioxins and dibenzofurans in incinerator exhausts

Murabayashi, Masayuki; Moesta, Hasso

doi:10.1021/es00028a020

Cited by 19 publications

(13 citation statements)

References 6 publications

(17 reference statements)

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“…The fact that the formation of many chlorinated species is frequently influenced by reactive surfaces supports this theory (14). Today the importance of non-gas-phase surface reactions are generally accepted in kinetic models of PCDD and PCDF formation (15)(16)(17).…”

Section: Introductionmentioning

confidence: 93%

Influence of Postcombustion Temperature Profiles on the Formation of PCDDs, PCDFs, PCBzs, and PCBs in a Pilot Incinerator

Faengmark¹,

Stroemberg²,

Berge³

et al. 1994

Environ. Sci. Technol.

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Section: Introductionmentioning

confidence: 93%

Influence of Postcombustion Temperature Profiles on the Formation of PCDDs, PCDFs, PCBzs, and PCBs in a Pilot Incinerator

Faengmark¹,

Stroemberg²,

Berge³

et al. 1994

Environ. Sci. Technol.

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“…So far dechlorination of PCBs, PCDDs and PCDF by using solid base systems (eg CaO) was only observed at elevated temperatures >200 °C 37. 38…”

Section: Resultsmentioning

confidence: 99%

“…Loiselle et al 37 used CaO and MgO at low temperature and atmospheric pressure to produce dechlorination of chlorobenzenes under hydrogen atmosphere. It was found that CaO, Na 2 O.SiO 2 would promote the dechlorination reaction of polychlorinated dibenzo‐ p ‐dioxin (PCDD) and polychlorinated dibenzofurans (PCDF) thermodynamically (>800 °C) by receiving chlorine atoms and that such organic materials as butane or butene would help the reaction by giving hydrogen in the reactions 38…”

Section: Resultsmentioning

confidence: 99%

Chemical removal of PCBs from water samples under ambient conditions

Nollet

Lutgen²,

Verstraete

2002

J of Chemical Tech & Biotech

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Liquids and sludges containing polychlorinated biphenyls (PCBs) can be treated to concentrate the PCBs in a solid residue. The latter can then be handled to destroy the PCBs. In the ®rst part of this work, procedures are explored by which 2,3,4-trichlorobiphenyl (TCB) and 2,2',3,3',4,5,6-heptachlorobiphenyl (HeCB) are insolubilised,¯occulated and removed from the water. The results demonstrate that application of Fe(III)-oxyhydroxide precipitation permits effective and reversible co-precipitation of TCB and HeCB. Fly ash from coal-®red thermal powerplants and CaO can be used as well for the rapid removal of TCB and HeCB. In the second part of this work, rapid insolubilisation followed by the degradation of TCB and HeCB by zero-valent iron powder in anaerobic batch systems is presented. Zero-valent iron was also used for the reductive dechlorination/remediation of TCB and HeCB sorbed on the¯y ash and CaO particles. Overall, this paper describes a methodology to rapidly concentrate the PCBs from water and to concomitantly detoxify them in the concentrate by a chemical reductive process under ambient conditions of pH and temperature.

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“…Hasselriis [127] also revealed that Cu catalyze the dechlorination of PCDD/Fs between 150-280 • C, in the presence of O 2 , forming the more toxic penta and hexa PCDDs and PCDFs from the octa forms. Modeling of PCDD/Fs formation [211], under low O 2 atmospheres, showed that the dechlorination takes place in the presence of CaO and Na-silicates as Cl scavengers. The calculated Gibbs energy for dechlorination of various congeners, using different oxides and silicates, led to conclude that the dechlorination of OCDF and OCDD is thermodynamically favored than that of TCDF and TCDD.…”

Section: Origin Generation and Fate Of Pcdd/fs And Pahs In Combustion Processesmentioning

confidence: 99%

Insights into PCDD/Fs and PAHs in Biomass Boilers Envisaging Risks of Ash Use as Fertilizers

Lopes

Proença

2020

Applied Sciences

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Since ashes are a possible source of Persistent Organic Pollutants (POPs) contamination, their application in soils must be subject to more study and control. In this scope, feed residual forest biomasses and biomass ashes, collected along one year in four biomass power stations, were characterized mainly for their polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) and Polycyclic Aromatic Hydrocarbons (PAHs) contents. The biomasses present concerning levels of Cl (0.04–0.28%) that may lead to PCDD/Fs formation. The biomasses also contain OCDD (29–260 ng/kg) and 1,2,3,4,6,7,8-HpCDD (35 ng/kg) that may contribute to increased Toxic Equivalents (TEQs) of ashes, possibly involving dichlorination and ash enrichment mechanisms. While the World Health Organization (WHO)2005-TEQs in bottom ashes (14–20 ng TEQ/kg) reaches the proposed limit (20 ng TEQ/kg) for ash use as fertilizers, in fly ashes (35–1139 ng TEQ/kg) the limit is exceeded. PAHs are below 0.02 mg/kg in bottom ashes and 1.5–2.5 mg/kg in fly ashes, complying with the proposed limit of 6 mg/kg. As bottom and fly ash streams may contain different ash flows, a clear definition of ash mixes is required. Correlations between unburned carbon (C), PAHs and PCDD/Fs were not found, which highlights the need for compulsory PCDD/Fs analysis in ashes, independently of their origin, burnout degree or levels of other contaminants. A sensitivity analysis was performed to evaluate the impact of handling non-detected values, which showed more impact for TEQs values close to the proposed regulatory limit of PCDD/Fs. These findings highlight the need to define reporting protocols of analytical results for risk assessments and conformity evaluation.

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Thermodynamic study on the reduction of the polychlorinated dibenzo-p-dioxins and dibenzofurans in incinerator exhausts

Cited by 19 publications

References 6 publications

Influence of Postcombustion Temperature Profiles on the Formation of PCDDs, PCDFs, PCBzs, and PCBs in a Pilot Incinerator

Influence of Postcombustion Temperature Profiles on the Formation of PCDDs, PCDFs, PCBzs, and PCBs in a Pilot Incinerator

Chemical removal of PCBs from water samples under ambient conditions

Insights into PCDD/Fs and PAHs in Biomass Boilers Envisaging Risks of Ash Use as Fertilizers

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