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Wang PY, Xu SX, Chen ZL, Chen T, Lin XQ, Ma YF, Zhang MM, Li XD. Inhibition of polychlorinated dibenzo-p-dioxins and dibenzofurans by phosphorus-containing compounds in model fly ash. CHEMOSPHERE 2020; 257:127168. [PMID: 32480089 DOI: 10.1016/j.chemosphere.2020.127168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 05/18/2020] [Accepted: 05/20/2020] [Indexed: 06/11/2023]
Abstract
Waste incineration is a preferred method in China to dispose the municipal solid waste, but controlling the production of highly toxic polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans effectively during incineration is both challenging and imperative. In this study, the suppression of PCDD/Fs by various phosphorus-containing compounds was explored, and the mechanisms responsible for the inhibition were studied in detail. The experiments took place in a lab-scale vertical tubular reactor at 350 °C under a simulated flue gas (12 vol% O2 in N2 flow), and both the off-gases and residues were collected for PCDD/Fs analysis. The scanning electron microscopy and energy-dispersive X-ray spectroscopy were used to characterize the reaction residues. The experimental results revealed that NH4H2PO4 and (NH4)2·HPO4 showed the highest inhibitory effect (57.2% and 57.3%, respectively) on the PCDD/Fs formation, followed by CaHPO4 with inhibition efficiency of 39.1%. In contrast, KH2PO4 and K2HPO4 barely inhibited the generation of the PCDD/Fs. The inhibitory effect of NH4H2PO4 and (NH4)2·HPO4 was similar to that of nitrogen-based inhibitors. At the same time, it was proven that the inhibitory activity of CaHPO4 might be due to the reaction of it with Cu2+ forming stable compounds.
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Affiliation(s)
- Pei-Yue Wang
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, China
| | | | - Zhi-Liang Chen
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN, 37215, USA
| | - Tong Chen
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, China.
| | - Xiao-Qing Lin
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, China
| | - Yun-Feng Ma
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, China
| | - Meng-Mei Zhang
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto, 6158510, Japan
| | - Xiao-Dong Li
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, China
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Zhang M, Fujimori T, Shiota K, Buekens A, Mukai K, Niwa Y, Li X, Takaoka M. Thermochemical formation of dioxins promoted by chromium chloride: In situ Cr- and Cl-XAFS analysis. JOURNAL OF HAZARDOUS MATERIALS 2020; 388:122064. [PMID: 31954297 DOI: 10.1016/j.jhazmat.2020.122064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 12/23/2019] [Accepted: 01/09/2020] [Indexed: 06/10/2023]
Abstract
Chromium is commonly found in the flue gases and ashes of Municipal Solid Waste Incineration. It has been reported as an active catalyst for the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) during de novo tests, yet its specific mode of action has remained unclear. This study aims to identify the effects of chromium chloride on the formation of PCDD/F and other chloro-aromatics and to elucidate the underlying reaction mechanisms. A series of de novo tests, conducted over a wide range of temperature (from 250 to 550 °C) and for four different oxygen contents (0, 5, 10, 20 %), confirmed the promoting effect of CrCl3 on the PCDD/F formation. In situ X-ray Absorption Fine Structure (XAFS) spectroscopy was applied to investigate the behavior of CrCl3 during heating, describing the entire picture of CrCl3-promoted formation pathways of dioxins. The effect of oxygen was studied by measuring XAFS spectra on samples heated at different oxygen concentrations. According to these spectra, chromium compounds play two key roles during dioxins formation: (a) chlorinating carbon, using chlorine derived from conversion of CrCl3 into Cr2O3, and further oxidation to Cr(VI), and (b) facilitating oxidative destruction of the carbon matrix, while reducing Cr(VI) to Cr2O3.
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Affiliation(s)
- Mengmei Zhang
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto, 6158510, Japan; State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Takashi Fujimori
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto, 6158510, Japan.
| | - Kenji Shiota
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto, 6158510, Japan
| | - Alfons Buekens
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Kota Mukai
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto, 6158510, Japan
| | - Yasuhiro Niwa
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, 3050801, Japan
| | - Xiaodong Li
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China.
| | - Masaki Takaoka
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto, 6158510, Japan
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Xiao H, Cheng Q, Liu M, Li L, Ru Y, Yan D. Industrial disposal processes for treatment of polychlorinated dibenzo-p-dioxins and dibenzofurans in municipal solid waste incineration fly ash. CHEMOSPHERE 2020; 243:125351. [PMID: 31756654 DOI: 10.1016/j.chemosphere.2019.125351] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 11/08/2019] [Accepted: 11/10/2019] [Indexed: 06/10/2023]
Abstract
Hazardous waste disposal is a serious environmental concern in China. Therefore, in this study, industrial trials were conducted in a low-temperature thermal degradation facility, a tunnel kiln, and a shaft kiln to effectively treat dioxins in municipal solid waste incineration (MSWI) fly ash. The results indicated that the low-temperature thermal degradation facility efficiently decomposed polychlorinated dibenzo-p-dioxins and dibenzofurans in the MSWI fly ash. Additionally, the concentrations of dioxins in the treated fly ash and exhaust gas were lower than the suggested standard limits and the degradation ratio of dioxins was ∼99%. Therefore, treated fly ash characterized by acceptable dioxin risks could be utilized for the production of non-fired building materials. The results from the tunnel kiln indicated complete decomposition of the dioxins in the firing and insulating sections. However, the addition of fly ash in the tunnel kiln increased the concentration of dioxins in the flue gas. This can be primarily attributed to the heterogeneous catalytic synthesis reaction in the low-temperature section of the tunnel kiln. The results from the shaft kiln indicated degradation of at least 22% of the dioxins in the ash. The dioxin concentration in the flue gas was lower than the national standard while that in the clinker was within a reasonable limit. Furthermore, the environmental risks were significantly reduced at fly ash addition ratios lower than 3%.
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Affiliation(s)
- Haiping Xiao
- North China Electric Power University, Beijing, 102206, China
| | - Qiyong Cheng
- North China Electric Power University, Beijing, 102206, China
| | - Meijia Liu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Li Li
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Yu Ru
- China Huaneng Clean Energy Research Institute, Beijing 102209, China
| | - Dahai Yan
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
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Liu L, Li W, Xiong Z, Xia D, Yang C, Wang W, Sun Y. Synergistic effect of iron and copper oxides on the formation of persistent chlorinated aromatics in iron ore sintering based on in situ XPS analysis. JOURNAL OF HAZARDOUS MATERIALS 2019; 366:202-209. [PMID: 30528590 DOI: 10.1016/j.jhazmat.2018.11.105] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 10/29/2018] [Accepted: 11/28/2018] [Indexed: 06/09/2023]
Abstract
Metal oxides, such as copper (II) oxide (CuO) and iron (III) oxide (Fe2O3), are dominant active components in fly ash during iron ore sintering. The potential synergetic effects of these oxides on the formation of chlorobenzenes (CBzs), polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were investigated based on in situ XPS analysis. Besides, the effect of trace metals, such as lead (II) oxide (PbO) and manganese (II) oxide (MnO) (0.5 wt.%), were also studied. The results demonstrated that CuO and Fe2O3 showed synergetic effect on the formation of chlorinated aromatics at a Cu/Fe mass ratio of 10:1. The in situ XPS results indicated that the synergistic effect of CuO and Fe2O3 with a Cu/Fe mass ratio of 10:1 might be attributed the enhanced oxidation and chlorination of carbon, contributing to a much higher production of CBzs, PCBs and PCDD/Fs. In addition, the quantities of polychlorinated dibenzofurans (PCDFs) were correlated linearly with those of CBzs and PCBs, which suggests the potential of CBzs and PCBs as indicator compounds for predicting PCDD/Fs emissions. Furthermore, the addition of PbO promoted the formation of CBzs while the yield of CBzs and PCBs decreased slightly after addition of MnO to the SFA.
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Affiliation(s)
- Lina Liu
- School of Energy and Power Engineering, Beihang University, Beijing, 100191, China; Energy and Environment International Center, Beihang University, Beijing, 100191, China
| | - Wenpei Li
- Beijing Key Laboratory of Bio-inspired Energy Materials and Devices, School of Space and Environment, Beihang University, Beijing, 100191, China
| | - Zesen Xiong
- Beijing Key Laboratory of Bio-inspired Energy Materials and Devices, School of Space and Environment, Beihang University, Beijing, 100191, China
| | - Dan Xia
- Beijing Key Laboratory of Bio-inspired Energy Materials and Devices, School of Space and Environment, Beihang University, Beijing, 100191, China
| | - Chengwu Yang
- Beijing Key Laboratory of Bio-inspired Energy Materials and Devices, School of Space and Environment, Beihang University, Beijing, 100191, China
| | - Wei Wang
- School of Environment, Tsinghua University, Beijing, 10084, China
| | - Yifei Sun
- Energy and Environment International Center, Beihang University, Beijing, 100191, China; Beijing Key Laboratory of Bio-inspired Energy Materials and Devices, School of Space and Environment, Beihang University, Beijing, 100191, China.
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Zhang M, Yang J, Buekens A, Olie K, Li X. PCDD/F catalysis by metal chlorides and oxides. CHEMOSPHERE 2016; 159:536-544. [PMID: 27341157 DOI: 10.1016/j.chemosphere.2016.06.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 06/04/2016] [Accepted: 06/10/2016] [Indexed: 06/06/2023]
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).
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Affiliation(s)
- Mengmei Zhang
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China
| | - Jie Yang
- Zhejiang Fangyuan Building Materials Technology Co., Ltd, Taizhou, China
| | - Alfons Buekens
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China; Chemical Engineering Department, Vrije Universiteit Brussel, Brussels, Belgium
| | - Kees Olie
- University of Amsterdam, Amsterdam, The Netherlands
| | - Xiaodong Li
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, China.
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Sun Y, Liu L, Fu X, Zhu T, Buekens A, Yang X, Wang Q. Mechanism of unintentionally produced persistent organic pollutant formation in iron ore sintering. JOURNAL OF HAZARDOUS MATERIALS 2016; 306:41-49. [PMID: 26686523 DOI: 10.1016/j.jhazmat.2015.11.059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 11/27/2015] [Accepted: 11/30/2015] [Indexed: 06/05/2023]
Abstract
Effects of temperature, carbon content and copper additive on formation of chlorobenzenes (CBzs) and polychlorinated biphenyls (PCBs) in iron ore sintering were investigated. By heating simulated fly ash (SFA) at a temperature range of 250-500°C, the yield of both CBzs and PCBs presented two peaks of 637ng/g-fly ash at 350°C and 1.5×10(5)ng/g-fly ash at 450°C for CBzs, and 74ng/g-fly ash at 300°C and 53ng/g-fly ash at 500°C. Additionally, in the thermal treatment of real fly ash (RFA), yield of PCBs displayed two peak values at 350°C and 500°C, however, yield of CBzs showed only one peak at 400°C. In the thermal treatment of SFA with a carbon content range of 0-20wt% at 300°C, both CBzs and PCBs obtained the maximum productions of 883ng/g-fly ash for CBzs and 127ng/g-fly ash for PCBs at a 5wt% carbon content. Copper additives also affected chlorinated aromatic formation. The catalytic activity of different copper additives followed the orders: CuCl2∙2H2O>>Cu2O>Cu>CuSO4>CuO for CBzs, and CuCl2∙2H2O>>Cu2O>CuO>Cu>CuSO4 for PCBs.
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Affiliation(s)
- Yifei Sun
- School of Chemistry and Environment, Beihang University, 37 Xueyuan Road, Beijing, China.
| | - Lina Liu
- School of Energy and Power Engineering, Beihang University, 37 Xueyuan Road, Beijing, China
| | - Xin Fu
- School of Chemistry and Environment, Beihang University, 37 Xueyuan Road, Beijing, China
| | - Tianle Zhu
- School of Chemistry and Environment, Beihang University, 37 Xueyuan Road, Beijing, China
| | - Alfons Buekens
- Department of Chemical Engineering, Free University of Brussels, Pleinlaan 2, 1050 Brussel, Belgium
| | - Xiaoyi Yang
- School of Energy and Power Engineering, Beihang University, 37 Xueyuan Road, Beijing, China
| | - Qiang Wang
- School of Energy and Power Engineering, Beihang University, 37 Xueyuan Road, Beijing, China
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Wang SJ, He PJ, Lu WT, Shao LM, Zhang H. Amino Compounds as Inhibitors of De Novo Synthesis of Chlorobenzenes. Sci Rep 2016; 6:23197. [PMID: 27034259 PMCID: PMC4817035 DOI: 10.1038/srep23197] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 03/02/2016] [Indexed: 11/09/2022] Open
Abstract
The inhibitory effects of four amino compounds on the formation of chlorobenzenes (CBzs)--dioxin precursors and indicators, and the inhibitory mechanisms were explored. The results show NH4H2PO4 can decrease the total yields of CBzs (1,2di-CBz, 1,3di-CBz, 1,4di-CBz, penta-CBz and hexa-CBz) by 98.1%±1.6% and 96.1%±0.7% under air and nitrogen flow. The inhibitory effects indicated by the total yields of CBzs follow the order NH4H2PO4 > NH4HF2 > (NH4)2SO4 > NH4Br under air flow and NH4H2PO4 ≈ (NH4)2SO4 ≈ NH4HF2 >NH4Br under nitrogen flow. The inhibition mechanism revealed by thermal analysis that CuCl2 was converted to CuPO3 by reacting with NH4H2PO4 below 200 °C, which can block the transfer of chlorine and formation of C-Cl bonds at 350 °C. The effects of the other three inhibitors were weaker because their reactions with CuCl2, which form other copper compounds, and the reaction of CuCl2 with carbon, which forms C-Cl bonds, were almost simultaneous and competitive. Oxygen influenced the yield of CBzs obviously, and the total yield of five CBzs sharply increased with oxygen. Because of their high efficiency, low environmental impact, low cost, and availability, amino compounds--especially NH4H2PO4--can be utilized as inhibitors of CBzs during incineration.
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Affiliation(s)
- Si-Jia Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, 1239 Siping Road, Shanghai 200092, P. R. China.,Institute of Waste Treatment and Reclamation, Tongji University, 1239 Siping Road, Shanghai 200092, P. R. China
| | - Pin-Jing He
- Institute of Waste Treatment and Reclamation, Tongji University, 1239 Siping Road, Shanghai 200092, P. R. China.,Centre for the Technology Research and Training on Household Waste in Small Towns &Rural Area, Ministry of Housing and Urban-Rural Development of P. R. China, 1239 Siping Road, Shanghai 200092, P. R. China
| | - Wen-Tao Lu
- State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, 1239 Siping Road, Shanghai 200092, P. R. China.,Institute of Waste Treatment and Reclamation, Tongji University, 1239 Siping Road, Shanghai 200092, P. R. China
| | - Li-Ming Shao
- Institute of Waste Treatment and Reclamation, Tongji University, 1239 Siping Road, Shanghai 200092, P. R. China.,Centre for the Technology Research and Training on Household Waste in Small Towns &Rural Area, Ministry of Housing and Urban-Rural Development of P. R. China, 1239 Siping Road, Shanghai 200092, P. R. China
| | - Hua Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, 1239 Siping Road, Shanghai 200092, P. R. China
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Fujimori T, Tanino Y, Takaoka M. Coexistence of Cu, Fe, Pb, and Zn oxides and chlorides as a determinant of chlorinated aromatics generation in municipal solid waste incinerator fly ash. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 48:85-92. [PMID: 24308371 DOI: 10.1021/es403585h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We investigated chemical determinants of the generation of chlorinated aromatic compounds (aromatic-Cls), such as polychlorinated biphenyls (PCBs) and chlorobenzenes (CBzs), in fly ash from municipal solid waste incineration. The influences of the following on aromatic-Cls formation in model fly ash (MFA) were systematically examined quantitatively and statistically: (i) inorganic chlorides (KCl, NaCl, CaCl2), (ii) base materials (SiO2, Al2O3, CaCO3), (iii) metal oxides (CuO, Fe2O3, PbO, ZnO), (iv) metal chlorides (CuCl2, FeCl3, PbCl2, ZnCl2), and (v) "coexisting multi-models." On the basis of aromatic-Cls concentrations, the ∑CBzs/∑PCBs ratio, and the similarity between distribution patterns, MFAs were categorized into six groups. The results and analysis indicated that the formation of aromatic-Cls depended strongly on the "coexistence condition", namely multimodels composed of not only metal chlorides, but also of metal oxides. The precise replication of metal chloride to oxide ratios, such as the precise ratios of Cu-, Fe-, Pb-, and Zn-chlorides and oxides, may be an essential factor in changing the thermochemical formation patterns of aromatic-Cls. Although CuCl2 acted as a promoter of aromatic-Cls generation, statistical analyses implied that FeCl3 also largely influenced the generation of aromatic-Cls under mixture conditions. Various additional components of fly ash were also comprehensively analyzed.
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Affiliation(s)
- Takashi Fujimori
- Department of Global Ecology, Graduate School of Global Environmental Studies, and ‡Department of Environmental Engineering, Graduate School of Engineering, Kyoto University , Katsura, Nisikyo-ku, 615-8540, Kyoto, Japan
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Chen X, Hu X, An L, Zhang N, Xia D, Zuo X, Wang X. Electrocatalytic Dechlorination of Atrazine Using Binuclear Iron Phthalocyanine as Electrocatalysts. Electrocatalysis (N Y) 2013. [DOI: 10.1007/s12678-013-0164-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Fujimori T, Tanino Y, Takaoka M. Thermochemical behavior of lead adjusting formation of chlorinated aromatics in MSW fly ash. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:2169-2176. [PMID: 23363298 DOI: 10.1021/es303663r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In this study, we examined the thermochemical role of Pb in the formation of chlorinated aromatics (aromatic-Cls) in MSW fly ash at 300-400 °C, a key temperature window for maximum yield. In the presence of lead oxide alone, aromatic-Cls formation was suppressed. One of the mechanisms of suppression was partial chlorination of PbO by an inorganic chlorine source in the solid phase, based on in situ Pb L3-edge X-ray absorption near-edge structure (XANES) data. In contrast, quantitative GC/MS measurements revealed that PbCl2 promoted aromatic-Cls formation to an extent that depends on the Pb concentration, the heating temperature, and the presence of other metal catalysts. We identified two mechanisms of aromatic-Cls formation triggered by PbCl2 in MSW fly ash. First, promotion can occur by the thermochemical partial oxidation of PbCl2. More specifically, real complex solid phase increases the thermochemical oxidation reactivity of PbCl2, based on in situ Pb L3-edge XANES data. Second, Cl K-edge X-ray absorption spectroscopy revealed a coexistent effect of PbCl2 with other metal catalysts such as CuCl2 and FeCl3. The presence of PbCl2 influences the balance of the bonding state of chlorine with Cu and Fe atoms at various temperatures. Thus, Pb in real MSW fly ash functions as an "adjuster" in the generation of aromatic-Cls, the nature of which depends on the lead oxide/chloride ratio and the presence of other metal catalysts.
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Affiliation(s)
- Takashi Fujimori
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University , Katsura, Nisikyo-ku, 615-8540 Kyoto, Japan
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Lu M, Luo YJ, Zhang ZZ, Xiao M, Zhang M. Evaluation of PCDD/Fs emissions during ceramic production: a laboratory study. JOURNAL OF HAZARDOUS MATERIALS 2012; 229-230:36-41. [PMID: 22727484 DOI: 10.1016/j.jhazmat.2012.05.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 04/15/2012] [Accepted: 05/16/2012] [Indexed: 06/01/2023]
Abstract
Because of the ubiquity of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in kaolinitic clays, the ceramic industry is considered to be a potential source of PCDD/Fs. However, studies on the emission of PCDD/Fs from ceramic production are still very scarce. In this study, PCDD/Fs emissions during ceramic production were investigated in an electric laboratory batch kiln. The results showed that the PCDD/Fs were completely removed from the ceramic pieces after 30 min of firing at the peak temperature of 1200°C. Nevertheless, on the mass and international toxic equivalent basis, 27.5% and 46.2% of the total PCDD/Fs amount in the raw clay were released into the atmosphere during firing, respectively. These PCDD/Fs were emitted into the air before the temperature was elevated to a level high enough for their destruction. Dechlorination reactions generated a broad distribution within the PCDD/Fs congeners including a variety of non-2,3,7,8-substituted ones. The emission of PCDD/Fs was decreased to 16.3 wt.% of the total PCDD/Fs amount in the raw clay, when the initial kiln temperature was enhanced to 600°C. The emission of PCDD/Fs could be reduced significantly in the presence of a glaze coating on the ceramic test piece. These results indicated that ceramic production is an un-neglectable source of PCDD/Fs in the environment.
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Affiliation(s)
- Mang Lu
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China
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Black RR, Meyer CPM, Yates A, Van Zweiten L, Mueller JF. Formation of artefacts while sampling emissions of PCDD/PCDF from open burning of biomass. CHEMOSPHERE 2012; 88:352-357. [PMID: 22503461 DOI: 10.1016/j.chemosphere.2012.03.046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2011] [Accepted: 03/03/2012] [Indexed: 05/31/2023]
Abstract
Emission factors for PCDD/PCDF determined from open combustion are used to estimate national emission budgets; therefore, it is important to have confidence in their accuracy. It has been suspected that artefacts may form due to the presence of hot metal surfaces of sampling equipment, thus skewing emission factors. In this study, emissions of PCDD/PCDF from open burning of forest biomass over a brick hearth were sampled. Five experiments were carried out using a portable sampler. Experiments were designed where the key variable, sample hood and inlet temperatures were manipulated. Other variables such as fuel origin, type and density were consistent. The measured concentration of PCDD/PCDF in the smoke samples ranged from 0.01 μg TEQ (t fuel)(-1) at the lowest maximum hood temperature (185°C) to 15 μg TEQ (t fuel)(-1) at the highest maximum hood temperature (598°C). when hood inlet temperatures exceeded 400°C emission factors were significantly elevated and this is attributed to the formation of artefacts that can cause the over estimation of emission factors. The increase in hood temperature also resulted in a change in the PCDD/PCDF congener and homologue profile of the emissions. For example at the lowest temperature (Fire 1) the PCDD/PCDF ratio measured was 50:1, whereas at the highest temperature (Fire 5) this ratio was about 0.53:1. When the sampler hood and inlet temperatures were kept in the normal operating range of <200°C, emission factors were comparable to those observed in many previous studies in Australia with emissions dominated by PCDD.
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Affiliation(s)
- R R Black
- The University of Queensland, National Research Centre for Environmental Toxicology, 39 Kessels Rd., Coopers Plains, QLD 4108, Australia.
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Lu M, Wang G, Zhang Z, Su Y. Characterization and inventory of PCDD/F emissions from the ceramic industry in China. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:4159-4165. [PMID: 22390402 DOI: 10.1021/es204639x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The ceramic industry is considered to be a potential source of dioxins (polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), considering the widespread distribution of dioxins in kaolinitic clays. Nevertheless, studies on the emission of dioxins from the ceramic industry are still very scarce. In this study, raw clays and stack gases from six typical ceramic plants in China were collected and analyzed to estimate the emission of dioxins from the ceramic industry. Dioxin profiles in raw clays were characterized by the domination of the congener octachlorodibenzo-p-dioxin (OCDD), and the contents of other congeners declined with the decreasing degree of chlorination. During the ceramic firing process, a considerable amount (16.5-25.1 wt % of the initial quantity in raw clays) of the dioxins was not destroyed and was released to the atmosphere. Dechlorination of OCDD generated a broad distribution within the PCDD congeners including a variety of non-2,3,7,8-substituted ones with the mass abundance of 0.4-3.6%. Based on the mean concentrations measured in this study, the inventory of PCDD/Fs from the manufacturing of ceramics on the Chinese scale was estimated to be 7.94 kg/year; the corresponding value on the I-TEQ basis is 133.6 g I-TEQ/year. This accounts for about 1.34% (I-TEQ basis) of the total emission of dioxins to the environment in China. The results suggest that the ceramic industry is a significant source of dioxins in the environment.
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Affiliation(s)
- Mang Lu
- School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen 333403, Jiangxi Province, China.
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Nganai S, Lomnicki SM, Dellinger B. Formation of PCDD/Fs from the copper oxide-mediated pyrolysis and oxidation of 1,2-dichlorobenzene. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:1034-1040. [PMID: 21174454 DOI: 10.1021/es102948f] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Formation of polychorinated dibenzo-p-dioxins (PCDDs) has been demonstrated to occur via surface-mediated reactions of chlorinated phenols. However, polychlorinated dibenzofurans (PCDFs) are observed in much lower yields in laboratory studies than in full-scale combustors where PCDFs are in higher concentrations than PCDDs. This has led to the suggestion that at least PCDFs are formed from elemental carbon in the de novo process. However, the potential for PCDF formation from reactions of chlorinated benzenes has been largely overlooked. In this study, we investigated the potential contribution of chlorinated benzenes to formation of PCDD/Fs using 1,2-dichlorobenzene as a surrogate for reactions of other chlorinated benzenes and CuO/silica (3 wt % Cu) as a surrogate for fly ash. Results were similar for oxidative and pyrolytic conditions with a slight increase in more chlorinated products under oxidative conditions. Reaction products included chlorobenzene, polychlorinated benzenes, phenol, 2-monochlorophenol (2-MCP), dichlorophenols, and trichlorophenols with yields ranging from 0.01 to 2% for the phenols and from 0.01 to 10% for chlorinated benzenes. 4,6-Dichlorodibenzo furan (4,6-DCDF) and dibenzofuran (DF) were observed in maximum yields of 0.2% and 0.5%, respectively, under pyrolytic conditions and 0.1% and 0.3%, respectively, under oxidative conditions. In previous studies of the pyrolysis of 2-MCP under identical conditions, 4,6-DCDF and dibenzo-p-dioxin (DD) were observed with maximum yields of ∼0.2% and ∼0.1%, respectively, along with trace quantities of 1-monochlorodibenzo-p-dioxin (1-MCDD). Under oxidative conditions, 1-MCDD, DD, and 4,6-DCDF were observed with maximum yields of 0.3%, 0.07% and 0.1%, respectively. When combined with the fact that measured concentrations of chlorinated benzenes are 10-100× that of chlorinated phenols in full-scale combustion systems, the data suggest surface-mediated reactions of chlorinated benzenes can be a significant source of PCDD/F emissions.
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Affiliation(s)
- Shadrack Nganai
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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Fan Y, Lu X, Ni Y, Zhang H, Zhao L, Chen J, Sun C. Destruction of polychlorinated aromatic compounds by spinel-type complex oxides. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:3079-3084. [PMID: 20334415 DOI: 10.1021/es9031437] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Destruction of polychlorinated aromatic compounds was carried out over spinel-type catalysts XY2O4 (where X = Mg, Ca, Cu, Ni, Zn, and Y = Al, Fe). The catalysts were characterized by XRD, nitrogen adsorption-desorption isotherms and FTIR. The performance of these catalysts toward the decomposition of hexachlorobenzene (HCB) and octachlorodibenzo-p-dioxin (OCDD) was evaluated in a closed system. The spinel-type catalyst with mesoporous structure demonstrated high catalytic activity for the hydrodechlorination of polychlorinated aromatic compounds. Among them, the copper-aluminum spinel (CuAl2O4), specifically calcined at 600 degrees C, exhibited the best activity. More than 85% dechlorination efficiency of HCB and 99% decomposition of polychlorinated dibenzodioxin (PCDD) were achieved at 250 degrees C for 30 min over the above catalyst which was more effective than the corresponding metallic copper and copper oxide catalysts during the thermal degradation of polychlorinated aromatic compounds. The correlation of catalytic performance to structural characteristics is discussed based on the detailed characterization. The simple preparation procedure and reasonable cost of the spinel-type catalysts present a good potential for the thermal treatment of polychlorinated aromatic pollutants at lower temperatures.
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Affiliation(s)
- Yun Fan
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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Oberg T, Bergbäck B, Filipsson M. Catalytic effects by metal oxides on the formation and degradation of chlorinated aromatic compounds in fly ash. CHEMOSPHERE 2008; 71:1135-1143. [PMID: 18061236 DOI: 10.1016/j.chemosphere.2007.10.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2007] [Revised: 10/11/2007] [Accepted: 10/18/2007] [Indexed: 05/25/2023]
Abstract
Polychlorinated benzenes, dibenzo-p-dioxins (PCDD), and dibenzofurans (PCDF) may be formed below the combustion temperature in fly ash from municipal solid waste incinerators (MSWI). Copper catalyzes this formation, possibly by the Deacon reaction. Many other elements are also Deacon catalysts or promoters, and here we report results from a statistically designed experiment with 15 metal oxides added to fly ash and heated at 300 degrees C for 2h in an air atmosphere. A resolution IV fractional factorial design with four replicates was completed in 36 runs with the oxides of magnesium, yttrium, titanium, vanadium, niobium, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, copper, zinc, and tin. All samples were analyzed for chlorinated benzenes and the results were evaluated by analysis of variance. The addition of copper significantly increased the amounts of the chlorinated benzenes, while cobalt, chromium and vanadium decreased the net formation. The oxides of zinc and iron seemed to have a slightly positive and negative effect respectively. The findings in this study seem to corroborate our previously reported results regarding the different catalytic effects of copper and chromium, and lack of a significant effect by nickel. Besides chromium, it also identifies cobalt and vanadium as potent catalysts for oxidative degradation of the chlorinated aromatic compounds found in MSWI fly ash.
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Affiliation(s)
- T Oberg
- University of Kalmar, School of Pure and Applied Natural Sciences, 391 82 Kalmar, Sweden.
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