Multivariate relationships between molecular descriptors and isomer distribution patterns of PCDD/Fs formed during MSW combustion.
The isomer distribution patterns of mono- to hepta-chlorinated dibenzo-p-dioxins (PC1-7DD) and dibenzofurans (PC1-7DF) in postcombustion zone flue gas during incineration of an artificial municipal solid waste in a laboratory-scale fluidized-bed reactor were evaluated. Bidirectional orthogonal projections to latent structures (O2PLS) was used to correlate a set of physicochemical properties and chlorine substitution descriptors with the objective to identify parameters correlated with postcombustion zone PCDD and PCDF formation. The most influential variable for the distribution of PCDD congeners was chlorine substitution in positions 1 and 3 (Cl1+3), and overall the chlorine substitution descriptors exerted a larger impact on PCDDs than on PCDFs. For the PCDF, chlorination of the 9-position was the most influential X-variable. Distinct clustering was observed and was most pronounced for PCDFs, dividing mostof the homologues into two or three subgroups of congeners. These subgroups seemed to correspond to the probability of formation by chlorophenol condensation. The sterically crowded dibenzofuran bay-sites (1- and 9-positions) were found to negatively influence PCDF formation, with chlorination of the 9-position having the greatest impact. Since PCDD/F toxicity is related to the lateral positions, elucidating the factors governing chlorination may be of great importance for detoxification of incineration byproducts.
Jansson
Stina
S
Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden. stina.jansson@chem.umu.se
Antti
Henrik
H
Marklund
Stellan
S
Tysklind
Mats
M
D001572:Benzofurans / Q000138:chemical synthesis* / Q000737:chemistry*; D002947:Cities; D017745:Incineration; D007536:Isomerism; D008956:Models, Chemical; D015999:Multivariate Analysis; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D025341:Principal Component Analysis; D012037:Refuse Disposal; D015203:Reproducibility of Results
D001572:Benzofurans; D000072317:Polychlorinated Dibenzodioxins; C023614:dibenzofuran