Details

Autor(en) / Beteiligte

• Guan, Xia
• Ghimire, Ajit
• Potter, Phillip M.
• Lomnicki, Slawomir M.

Titel

Role of Fe2O3 in fly ash surrogate on PCDD/Fs formation from 2-monochlorophenol

Ist Teil von

• Chemosphere (Oxford), 2019-07, Vol.226, p.809-816

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2019

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The correlation between the content and morphology of Fe2O3 and the yields of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) was studied in this work. Three fly ash surrogates containing 1%, 2.5%, and 4% of Fe2O3 were prepared and their effects on PCDD/Fs formation were investigated and compared to our previously studied 5% iron oxide sample using 2-monochlorophenol precursor model. As the intermediate of PCDD/Fs, environmentally persistent free radical formation propensity was correlated with the PCDD/Fs formation yields for different iron oxide samples. PCDD/Fs yield increases exponentially with the increasing iron content under pyrolytic conditions. On the contrary, low iron oxide content promotes oxidation and lowers yields of PCDD/Fs. Changing iron oxide clusters' morphology (crystallinity and cluster size) affects the mechanism of PCDD/Fs formation – on larger crystallites, a bidentate chemisorption of precursor is preferred leading to lower chlorinated congeners, while smaller clusters promote formation of PCDFs through mixed monodentate-bidentate surface species, resulting in formation of congeners with 1 chlorine more. This study further confirms the propensity of iron oxide to predominantly form PCDFs. The iron content also defines PCDDs:PCDFs ratio. •The crystallinity and cluster size increases with increasing Fe2O3 content in fly ash, which enhances total PCDD/Fs yield.•The PCDD/F yield is positively correlated with the concentration of EPFRs, which are intermediates in the formation of PCDD/Fs.•The content of iron oxide in fly ash determines PCDFs congener pattern and the ratio of PCDDs to PCDFs.