title: Biofuel-Promoted Polychlorinated Dibenzodioxin/furan Formation in an Iron-Catalyzed Diesel Particle Filter.
abstract: Iron-catalyzed diesel particle filters (DPFs) are widely used for particle abatement. Active catalyst particles, so-called fuel-borne catalysts (FBCs), are formed in situ, in the engine, when combusting precursors, which were premixed with the fuel. The obtained iron oxide particles catalyze soot oxidation in filters. Iron-catalyzed DPFs are considered as safe with respect to their potential to form polychlorinated dibenzodioxins/furans (PCDD/Fs). We reported that a bimetallic potassium/iron FBC supported an intense PCDD/F formation in a DPF. Here, we discuss the impact of fatty acid methyl ester (FAME) biofuel on PCDD/F emissions. The iron-catalyzed DPF indeed supported a PCDD/F formation with biofuel but remained inactive with petroleum-derived diesel fuel. PCDD/F emissions (I-TEQ) increased 23-fold when comparing biofuel and diesel data. Emissions of 2,3,7,8-TCDD, the most toxic congener [toxicity equivalence factor (TEF) = 1.0], increased 90-fold, and those of 2,3,7,8-TCDF (TEF = 0.1) increased 170-fold. Congener patterns also changed, indicating a preferential formation of tetra- and penta-chlorodibenzofurans. Thus, an inactive iron-catalyzed DPF becomes active, supporting a PCDD/F formation, when operated with biofuel containing impurities of potassium. Alkali metals are inherent constituents of biofuels. According to the current European Union (EU) legislation, levels of 5 μg/g are accepted. We conclude that risks for a secondary PCDD/F formation in iron-catalyzed DPFs increase when combusting potassium-containing biofuels.
authors.forename: Norbert V
authors.initials: NV
authors.lastname: Heeb
authors.affiliation: §Chemical Engineering Department, University of Alicante, 03080 Alicante, Spain.
authors.forename: Maria Dolores
authors.initials: MD
authors.lastname: Rey
authors.forename: Markus
authors.initials: M
authors.lastname: Zennegg
authors.forename: Regula
authors.initials: R
authors.lastname: Haag
authors.forename: Adrian
authors.initials: A
authors.lastname: Wichser
authors.forename: Peter
authors.initials: P
authors.lastname: Schmid
authors.forename: Cornelia
authors.initials: C
authors.lastname: Seiler
authors.forename: Peter
authors.initials: P
authors.lastname: Honegger
authors.forename: Kerstin
authors.initials: K
authors.lastname: Zeyer
authors.forename: Joachim
authors.initials: J
authors.lastname: Mohn
authors.affiliation: ∥Laboratory for Exhaust Emission Control, University of Applied Sciences Biel (UASB), Gwerdtstrasse 5, CH-2560 Nidau, Switzerland.
authors.forename: Samuel
authors.initials: S
authors.lastname: Bürki
authors.affiliation: ∥Laboratory for Exhaust Emission Control, University of Applied Sciences Biel (UASB), Gwerdtstrasse 5, CH-2560 Nidau, Switzerland.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zimmerli
authors.affiliation: ∥Laboratory for Exhaust Emission Control, University of Applied Sciences Biel (UASB), Gwerdtstrasse 5, CH-2560 Nidau, Switzerland.
authors.forename: Jan
authors.initials: J
authors.lastname: Czerwinski
authors.affiliation: ⊥Technik Thermischer Maschinen (TTM), Fohrhölzlistrasse 14b, CH-5443 Niederrohrdorf, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Mayer
mesh_terms: D000393:Air Pollutants / Q000032:analysis; D056804:Biofuels / Q000032:analysis*; D002384:Catalysis; D002713:Chlorine / Q000737:chemistry; D004777:Environment; D005374:Filtration / Q000295:instrumentation*; D005663:Furans / Q000737:chemistry*; D005742:Gasoline / Q000032:analysis*; D007501:Iron / Q000737:chemistry*; D010084:Oxidation-Reduction; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000737:chemistry; D001335:Vehicle Emissions / Q000032:analysis
chemical_list: D000393:Air Pollutants; D056804:Biofuels; D005663:Furans; D005742:Gasoline; D000072317:Polychlorinated Dibenzodioxins; D001335:Vehicle Emissions; D002713:Chlorine; D007501:Iron; C039281:furan