Dynamic Change of Copper in Fly Ash during de Novo Synthesis of Dioxins

Takaoka, Masaki; Shiono, Atsuhiro; Nishimura, Kohei; Yamamoto, Takashi; Uruga, Tomoya; Takeda, Nobuo; Tanaka, Tsunehiro; Oshita, Kazuyuki; Matsumoto, Tadao; Harada, Hidenori

doi:10.1021/es048019f

Cited by 101 publications

(98 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, cupric chloride was partly and totally reduced (to CuCl) at 300 and 400 C, respectively. Analysis of Cl K-edge NEXAFS showed evidence that the previously reported reduction of cupric chloride 4,15 triggered chlorination of carbon by chlorine from copper. This also indicated that the chlorination potential was weakened by reduction to CuCl.…”

Section: Comparison Of Influences Among Heavy Metal Chloridesmentioning

confidence: 77%

Chlorination Mechanism of Carbon during Dioxin Formation Using Cl-K Near-edge X-ray-absorption Fine Structure

et al. 2010

Self Cite

View full text Add to dashboard Cite

Many environmental organic chemicals have chloride in their structure. Thus, researching the chlorination mechanism of carbon is of interest. Dioxins are typically concentrated in fly ash collected from the post-combustion zone during the operation of municipal solid waste incinerators. In this study, we report the application of Cl-K near-edge X-rayabsorption fine structure (NEXAFS) in determining the chlorination mechanism of carbon in fly ash. The separation of a chloride-carbon (C-Cl) bond was readily recognizable as a peak in the Cl-K NEXAFS spectrum. Chlorination effects could be estimated using Cl K-edge NEXAFS with no dependence on metal species. Analysis of Cl K-edge NEXAFS spectra showed the reduction of copper(II) chloride at 300 C and oxidation of iron(III) chloride at 400 C in connection with the chlorination of carbon.

show abstract

Section: Comparison Of Influences Among Heavy Metal Chloridesmentioning

confidence: 77%

Chlorination Mechanism of Carbon during Dioxin Formation Using Cl-K Near-edge X-ray-absorption Fine Structure

et al. 2010

Self Cite

View full text Add to dashboard Cite

show abstract

“…CBzs and PCBs do not contain oxygen in their structures. The generation of aromatic-Cls containing no oxygen was thought to be mainly influenced by the oxidative destruction of macromolecular carbon, which might be caused by gaseous oxygen and the catalytic role of cupric chloride (Takaoka et al, 2005;). Concentrations of ΣPCDFs and ΣPCBs from graphite at 400°C were 22 and 9 times higher, respectively, than that at 300°C.…”

Section: The Generation Of Pcdds Pcdfs Pcbs and Cbzsmentioning

confidence: 99%

Influence of the Properties of Macromolecular Carbon on de Novo Synthesis of PCDDs, PCDFs, PCBs, and Chlorobenzenes

Fujimori

Nishimura

Oshita

et al. 2014

Aerosol Air Qual. Res.

Self Cite

View full text Add to dashboard Cite

We examined the influence of the properties of macromolecular carbon on thermochemical de novo synthesis of toxic chlorinated aromatic compounds (aromatic-Cls), such as polychlorinated dibenzo-p-dioxins (PCDDs), furans (PCDFs), biphenyls (PCBs), and chlorobenzenes (CBzs). Six types of macromolecular carbons were prepared. Some activated carbon samples were modified by chemical solvents, such as nitric acid, hydrogen peroxide, sulfuric acid, and urea solutions, to change the properties of the activated carbon. We characterized six macromolecular carbons by surface area (8.8-1540 m 2 /g), free radicals (N s = not analyzed to 67.0 × 10 19 g -1 , g = 2.0011-2.0098), and functional groups (O-H, C-H, C=O, C=C, C-O, and C-OH). Concentrations of aromatic-Cls at 300-400°C, such as PCDDs, PCDFs, PCBs, and CBzs, were clearly influenced by the type of macromolecular carbon. Their distribution between the ash/gas phases implied that increasing the surface area mainly enhanced the adsorption capacity of macromolecular carbon, while increasing the number of free radicals mainly enhance the reaction activity of macromolecular carbon. The PCDD/PCDF ratio suggested that various modifications of macromolecular carbon contributed to the generation of PCDDs in addition to the catalytic behavior of copper. Under most conditions, the surface area of macromolecular carbon did not have a strong correlation with the generation of PCDDs, PCBs, and CBzs, but it did show have a correlation with the generation of PCDFs. One of the destructive effects of aromatic-Cls resulted from the free radicals in macromolecular carbon. The C=O bond (ca. 1720 cm -1 ) functional group in macromolecular carbon had no strong correlation with the generation of aromatic-Cls, because free radicals had a destructive effect. The functionalities of ether (C-O) or phenolic OH (C-OH) in macromolecular carbon were causative factors in the generation of oxygen-containing aromatic-Cls, such as PCDDs and PCDFs.

show abstract

“…According to earlier work, the Cu element (Table 1) determined by the elemental analysis is probably present as the chloride and oxide forms. 31) It is therefore possible that fine-particles of KCl and copper chlorides might react with C( ) to form C-O…”

Section: Possible Routes For De Novo Synthesis Of Organicmentioning

confidence: 99%

Properties of Dust Particles Sampled from Windboxes of an Iron Ore Sintering Plant: Surface Structures of Unburned Carbon

et al. 2006

View full text Add to dashboard Cite

Aiming to understand the formation mechanism of dioxins in the iron ore sintering process, dust samples obtained from some windboxes of a commercial iron ore sintering plant have been characterized with a powder X-ray diffraction (XRD), by the transmission electron microscope (TEM) equipped with an electron energy loss spectroscopy (EELS), and by the temperature-programmed desorption (TPD) and temperatureprogrammed oxidation (TPO) techniques. The elemental and XRD analyses reveal that the content of the Cl present in the samples ranges from 0.075 mass%-dry to 5.1 mass%-dry and tends to be higher at smaller dust particles, and that some of the Cl exists as KCl with the average crystalline size between 40 nm and 50 nm. Dust samples also contain a significant amount of unburned carbon, and the smallest dust particles, Ͻ500 mm, show the highest C contents in many cases and consist partly of C, K, and Cl elements. The TPD and TPO experiments exhibit that the dust samples have several types of oxygen functional forms on the carbon surface, and the proportion of carboxyl and lactone/acid anhydride groups, which can be partly decomposed into CO 2 and carbon active sites at 150 to 500°C, tends to be larger at smaller dust particles. On the basis of the above results, the formation mechanism of chlorinated organic compounds including dioxins is discussed in term of interactions among HCl (and/or Cl 2 ), metallic chlorides, and carbon active sites.

show abstract

Dynamic Change of Copper in Fly Ash during de Novo Synthesis of Dioxins

Cited by 101 publications

References 27 publications

Chlorination Mechanism of Carbon during Dioxin Formation Using Cl-K Near-edge X-ray-absorption Fine Structure

Chlorination Mechanism of Carbon during Dioxin Formation Using Cl-K Near-edge X-ray-absorption Fine Structure

Influence of the Properties of Macromolecular Carbon on de Novo Synthesis of PCDDs, PCDFs, PCBs, and Chlorobenzenes

Properties of Dust Particles Sampled from Windboxes of an Iron Ore Sintering Plant: Surface Structures of Unburned Carbon

Contact Info

Product

Resources

About