title: PCDD/F catalysis by metal chlorides and oxides.
abstract: Model fly ash (MFA) samples were composed of silica, sodium chloride, and activated carbon, and doped with metal (0.1 wt% Cu, Cr, Ni, Zn and Cd) chloride or oxide. Each sample was de novo tested at 350 °C for 1 h, in a flow of gas (N2, N2 + 10% O2, +21% O2 or +10% H2) to investigate the effect of metal catalyst and gas composition on PCDD/F formation. Total PCDD/F yield rises rapidly with oxygen content, while the addition of hydrogen inhibits the formation and chlorination of PCDD/F. The amount of PCDD on average rises linearly with the oxygen concentration, while that of PCDF follows a reaction order of about 1/2; thus the PCDF to PCDD ratio drops when more oxygen becomes available. Some samples do not follow this trend. Chlorides are much more active than oxides, yet there are marked differences between individual metals. Principal component analysis (PCA) was applied to study the signatures from all samples, showing their unique specificity and diversity. Each catalyst shows a different signature within its individual homologue groups, demonstrating that these signatures are not thermodynamically controlled. Average congener patterns do not vary considerably with oxygen content changing from oxidising (air) to reducing (nitrogen, hydrogen).
authors.affiliation: State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China.
authors.forename: Mengmei
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Zhejiang Fangyuan Building Materials Technology Co., Ltd, Taizhou, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China; Chemical Engineering Department, Vrije Universiteit Brussel, Brussels, Belgium.
authors.forename: Alfons
authors.initials: A
authors.lastname: Buekens
authors.affiliation: University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Kees
authors.initials: K
authors.lastname: Olie
authors.affiliation: State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China. Electronic address: lixd@zju.edu.cn.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Li
mesh_terms: D002244:Carbon; D002384:Catalysis; D002712:Chlorides / Q000737:chemistry*; D060729:Coal Ash; D000072318:Dibenzofurans / Q000737:chemistry*; D017745:Incineration; D008670:Metals / Q000737:chemistry*; D009584:Nitrogen / Q000032:analysis; D010087:Oxides / Q000737:chemistry*; D010100:Oxygen / Q000032:analysis; D000072317:Polychlorinated Dibenzodioxins / Q000737:chemistry*
chemical_list: D002712:Chlorides; D060729:Coal Ash; D000072318:Dibenzofurans; D008670:Metals; D010087:Oxides; D000072317:Polychlorinated Dibenzodioxins; D002244:Carbon; D009584:Nitrogen; D010100:Oxygen
keywords: Catalysis; Fly ash; Metal chloride; Metal oxide; PCDD/F