Influence of metal oxides on PCDD/Fs formation from pentachlorophenol

Qian, Yong; Zheng, Minghui; Liu, Wenbin; Ma, Xiaodong; Zhang, Bing

doi:10.1016/j.chemosphere.2004.12.068

Cited by 48 publications

(36 citation statements)

References 37 publications

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“…Pentachlorophenol (PCP) was purified to remove PCDE and PCDD/F impurities (Qian et al 2005). Prior to the experiments, the silicon dioxide was Soxhlet extracted with toluene, air-dried at room temperature, and then heated at 700°C for 6 h. The copper oxide was ground in a mortar before use.…”

Section: Methodsmentioning

confidence: 99%

Influence of iron and copper oxides on polychlorinated diphenyl ether formation in heterogeneous reactions

Liu

Shen

Zhang

et al. 2013

Environ Sci Pollut Res

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Polychlorinated diphenyl ether (PCDE) has attracted great attention recently as an important type of environmental pollutant. The influence of iron and copper oxides on formation of PCDEs was investigated using laboratory-scale flow reactors under air and under nitrogen at 350°C, a temperature corresponding to the post-combustion zone of a municipal solid waste incinerator. The results show that the 2,2′,3,4,4′,5,5′,6-otachlorodiphenyl ether (OCDE) formed from the condensation of pentachlorophenol (PCP) and 1,2,4,5-tetrachlorobenzene (Cl 4

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Section: Methodsmentioning

confidence: 99%

Influence of iron and copper oxides on polychlorinated diphenyl ether formation in heterogeneous reactions

Liu

Shen

Zhang

et al. 2013

Environ Sci Pollut Res

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“…To the contrary, the existence of Pb (chloride and oxide) and Ca (oxide) might inhibit the formation of PCDD/Fs (Qian et al, 2005;Fujimori et al, 2009). But for Al, conflict roles (i.e., either act as a catalyst or inhibitor) have been found in PCDD/F formation processes (Hinton and Lane, 1991;Gullett et al, 1992;Qian et al, 2005). In this study, the co-existence of the above five metal contents warrants the need for further investigation in their roles on PCDD/F formation processes.…”

Section: Ionic Constituents Containing In Wb Dustsmentioning

confidence: 93%

“…Among these five metal contents, several studies have shown that the existence of Fe and K might lead to the increase in PCDD/Fs formation (Hinton and Lane, 1991;Nganai et al, 2009;Fujimori et al, 2009). To the contrary, the existence of Pb (chloride and oxide) and Ca (oxide) might inhibit the formation of PCDD/Fs (Qian et al, 2005;Fujimori et al, 2009). But for Al, conflict roles (i.e., either act as a catalyst or inhibitor) have been found in PCDD/F formation processes (Hinton and Lane, 1991;Gullett et al, 1992;Qian et al, 2005).…”

Section: Ionic Constituents Containing In Wb Dustsmentioning

confidence: 99%

Identification the Content of the Windbox Dust Related to the Formation of PCDD/Fs during the Iron Ore Sintering Process

Kuo

Chen

Yang³

et al. 2011

Aerosol Air Qual. Res.

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This study measured the contents of the ionic and elemental constituents, and the chemical compounds containing in windbox (WB) dusts collected from a commercial iron ore sintering plant, then the results were used to identify possible PCDD/Fs formation pathways in the WB. We found that the abundance in both KCl and NaCl may provide a suitable condition for de novo synthesis of PCDD/Fs in the WB. Al, Fe, K, Ca, and Pb were the top five contents in WB16 dusts, but the co-existence of the above five metal contents warrants the need for further investigation on their roles in PCDD/F formation processes in the future. Although a low concentration of Cu was detected, it might be of importance to PCDD/Fs formation inside the WB. A total of 29 chemical compounds were identified. Among them, several oxygenated organic compound might be associated with PCDD/F formations at the beginning stage, but the roles of aromatic oxygenates on the formation of PCDD/Fs required further investigation. Finally, possible de novo synthesis pathways of PCDD/Fs were proposed based on the above findings. However, the above pathways are required further laboratory studies for validation before possible formation suppression approaches can be determined.

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“…Various chemical inhibitors for reducing PCDD/F formation have been tested on both laboratory-and pilot-plant-scales. The alkali earth metal oxides (CaO, BaO and MgO) have been reported to suppress PCDD/F formation from PCP in a laboratory-scale reactor [5,14]. However, the suppressing efficiencies of them is CaO ≈ BaO > MgO.…”

Section: Introductionmentioning

confidence: 98%

“…Liu et al [13] found that CaO not only absorbed and decomposed dioxin precursors, but also absorbed HCl and prevented the formation of Cl 2 from HCl. Qian et al [5] speculated that the effects of basic compounds such as CaO, BaO, and Ca(OH) 2 on PCDD/F formation could be attributed to suppression of PCDD/F formation through acid-base reactions and other physical and chemical interactions between the precursor PCP and basic metal compounds. While Ruokojârvi et al [39] proposed that the urea molecule itself, or NH 3 or HNCO may form the complex with the catalyzing metal.…”

Section: Possible Mechanism Of Synergetic Inhibitionmentioning

confidence: 99%

Synergetic inhibition of PCDD/F formation from pentachlorophenol by mixtures of urea and calcium oxide

et al. 2016

Journal of Hazardous Materials

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h i g h l i g h t s• Mixed CaO/urea have a synergetic inhibition effect for PCDD/Fs formation from PCP.• 5-20% urea reaction systems obtained the better synergetic inhibition effect.• 2,3,7,8-PCDD congeners were the dominant products in eight reaction systems.• Intermediates could promote the acid-base reaction to realize synergetic inhibition. a r t i c l e i n f o b s t r a c tChlorophenols are structurally similar to PCDD/Fs and have been considered as highly potential precursors for PCDD/Fs formation. The suppressing effects of PCDD/F formation from pentachlorophenol (PCP) were investigated on various mass ratios of CaO and urea. The total concentration of 2,3,7,8-PCDD/Fs, mostly dominated by OCDD, was determined to be 48.58-10186 ng/mg in inhibitor-reaction systems, being much lower than that in blank reaction system (75654 ng/mg). Interestingly, compared with pure CaO and urea reaction system, the concentration and TEQ of formed 2,3,7,8-PCDD/Fs in mixed urea/CaO reaction system were lower, especially with 5-20% urea reaction systems being respectively at decrease by 96.5-99.4% and 99.2-99.7%. The suppression efficiency of TEQ in 5-20% urea reaction systems could be always approximately 100% under 250-350• C. These results suggested that mixed inhibitors, especially 5-20% urea inhibitors, have a synergetic inhibition effect for PCDD/Fs formation from PCP. Mixed inhibitor generated several intermediates, involving CO 2 , H 2 O, NH 3 , Ca(OH) 2 , CaCO 3 , HNCO, biuret and ammelide. The complex between PCP and Ca, N-doped species, lower chlorinated phenols and benzenediol, and organic acids were also determined. Synergetic inhibition mechanism may be attributed to accelerated facilitation of acid-base reaction and N doping. The decomposition of PCP itself also contributes to prevent PCDD/Fs formation.

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Influence of metal oxides on PCDD/Fs formation from pentachlorophenol

Cited by 48 publications

References 37 publications

Influence of iron and copper oxides on polychlorinated diphenyl ether formation in heterogeneous reactions

Influence of iron and copper oxides on polychlorinated diphenyl ether formation in heterogeneous reactions

Identification the Content of the Windbox Dust Related to the Formation of PCDD/Fs during the Iron Ore Sintering Process

Synergetic inhibition of PCDD/F formation from pentachlorophenol by mixtures of urea and calcium oxide

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