| Autor: |
Wikström, Evalena1,2, Ryan, Shawn, Touati, Abderrahmane3, Gullett, Brain K.2 gullet.brain@epa.gov |
| Předmět: |
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| Zdroj: |
Environmental Science & Technology. 4/1/2004, Vol. 38 Issue 7, p2097-2101. 5p. |
| Abstrakt: |
The aim of this study was to investigate the role of in situ formed soot deposits generated during a combustion process for the formation of polycholorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/Fs). In sity formed soot deposits were generated in an entrained flow reactor by using a sooting methane (CH4) flame (sooting phase), with or without chlorine doped into the flame, and fly ash added into the gas phase. The presence of fly ash in the soot deposit was found to be critical, as a catalyst for formation and/or a chlorinating agent. The presence of chlorinated aromatic structures in the soot matrix was not enough to promote do novo formation of PCDDs/Fs without the presence of fly ash. PCDFs were formed via direct release of the molecule backbone structure from the soot. PCDDs were formed via a similar mechanism as well as an equally important formation pathway of condensation reactions of C6 compounds. The formation rate of the soot/ash deposit were formed, suggesting a persistent do novo formation occurring for a long time after the sooting incidences (memory effect). [ABSTRACT FROM AUTHOR] |
| Databáze: |
GreenFILE |
| Externí odkaz: |
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