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Kevin C. Jones - One of the best experts on this subject based on the ideXlab platform.
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Observations on historical, contemporary, and natural PCDD/Fs.
Environmental science & technology, 2004Co-Authors: Nicholas J. L. Green, Ashraf Hassanin, A. E. Johnston, Kevin C. JonesAbstract:PCDD/Fs were determined in samples of archived surface soils collected from different locations around the world in the early 1880s, in contemporary surface soils from around the world, in archived subsurface soils collected at Rothamsted Experimental Station in the 1870/1880s, and in sections of peat core deposited between 5000 BP and the present. PCDD/Fs were detected in most of the samples. The potential sources and implications of the levels and mixtures of PCDD/Fs present in the samples are discussed. The homologue and isomer patterns observed in most of the contemporary European surface soils are commonly observed for European air samples and soil samples. The homologue pattern in the Rothamsted surface soils collected in the 1800s was similar, suggesting that similar sources of atmospheric emissions of PCDD/Fs were operating in the UK in the 1800s as currently. Very different patterns, dominated by OCDD and with contributions of HPCDD and HxCDD, were found in some other samples. It is proposed that the PCDD/Fs present in the subsurface Rothamsted soils, archived (1880s) surface soils from Illinois and the Congo, clay beneath the peat bog (deposited 5000 BP), and possibly surface soil samples from Thailand and Australia are of a natural origin. The most abundant TeCDD/F congeners measured in the peat samples here were also those observed by previous workers who studied a Canadian peat bog and are consistent with the microbially mediated oxidative coupling of chlorophenols. The study provides evidence for the widespread occurrence of PCDD/Fs in the environment prior to 1900 and for a complex array of sources (including natural) and environmental transformation processes.
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pentachlorophenol pcp and chloranil as PCDD f sources to sewage sludge and sludge amended soils in the uk
Chemosphere, 1997Co-Authors: Ruth E. Alcock, Kevin C. JonesAbstract:Pentachlorophenol (PCP) and its derivatives (NaPCP and PCPL) contain PCDD/Fs (predominantly Hp-CDD/Fs and OCDD/F) as impurities. Reported concentrations of 2,3,7,8-substituted congeners in technical PCP (1000 – 3000 μg TEQ/kg) are significantly higher than those reported in PCP products such as NaPCP (84 – 510 μg TEQ/kg). PCP-based textile preservatives (particularly associated with imported cotton textiles) probably represent an important PCDD/F source to sewage sludge. Chloranil and chloranil-based dyes and pigments can contain significant levels of PCDD/F impurities as predominantly OCDD. Associated dyes and pigment contain lower PCDD/F concentrations (2 – 200 μg TEQ/kg) than pure chloranil (300 – 2900 μg TEQ/kg). The use of water-based textile dyes containing chloranil in a given catchment could represent a significant source of higher molecular weight PCDD/F congeners to the resulting sewage sludge. In addition to sewage sludge, application of other types of organic amendments (e.g. farm yard manure), paper waste sludge and textile waste could represent important sources of PCDD/Fs to agricultural soils in the UK.
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Pentachlorophenol (PCP) and chloranil as PCDD/F sources to sewage sludge and sludge amended soils in the UK
Chemosphere, 1997Co-Authors: Ruth E. Alcock, Kevin C. JonesAbstract:Pentachlorophenol (PCP) and its derivatives (NaPCP and PCPL) contain PCDD/Fs (predominantly Hp-CDD/Fs and OCDD/F) as impurities. Reported concentrations of 2,3,7,8-substituted congeners in technical PCP (1000 – 3000 μg TEQ/kg) are significantly higher than those reported in PCP products such as NaPCP (84 – 510 μg TEQ/kg). PCP-based textile preservatives (particularly associated with imported cotton textiles) probably represent an important PCDD/F source to sewage sludge. Chloranil and chloranil-based dyes and pigments can contain significant levels of PCDD/F impurities as predominantly OCDD. Associated dyes and pigment contain lower PCDD/F concentrations (2 – 200 μg TEQ/kg) than pure chloranil (300 – 2900 μg TEQ/kg). The use of water-based textile dyes containing chloranil in a given catchment could represent a significant source of higher molecular weight PCDD/F congeners to the resulting sewage sludge. In addition to sewage sludge, application of other types of organic amendments (e.g. farm yard manure), paper waste sludge and textile waste could represent important sources of PCDD/Fs to agricultural soils in the UK.
Guoping Changchien - One of the best experts on this subject based on the ideXlab platform.
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persistent organic pollutant reductions from a diesel engine generator fueled with waste cooking oil based biodiesel blended with butanol and acetone
Aerosol and Air Quality Research, 2017Co-Authors: Jenhsiung Tsai, Shuijen Chen, Guoping Changchien, Bocheng Jheng, Kuolin Huang, Jueiyu ChiuAbstract:ABSTRACTThis investigation focuses on the effects on emissions of persistent organic pollutants (POPs) (polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) and polybrominated diphenyl ethers (PBDEs)) from a diesel engine fuelled by 20 vol% waste cooking oil-based biodiesel (W20) blended with various fractions of dehydrate/hydrous butanol (B/B′) and acetone (A/A′). The emission concentrations of the POPs were in the order PBDE ≫ PBDD/F > PCB > PCDD/F, regardless of the blending fuel or engine load. The POP with highest concentration was PBDE, being 2–3 times that of the others. Conversely, the magnitude of emitted toxicity followed the order PCDD/F > PCB ≈ PBDD/F, while PCDD/F emissions had about 10 times the toxicity concentrations of PCBs and PBDD/Fs. Among the dioxin compounds, the emissions of PCDDs represented 46–73% (average 57%) and 50–72% (average 59%) of total PCDD/F mass and toxicity concentrations, respectively, and were which and were thus significantly higher than those of PCDFs. The non-ortho-PCB contributed almost all toxicity (~100%) of 14 dioxin-like-PCBs, even though its contribution in mass was only 9–32% (average 16%) among the congeners. Similarly, PBDFs accounted for ~100% of toxicity of PBDD/Fs. Additionally, deca-BDEs contributed to most of the mass emissions of PBDEs (47.0–90.5%, 82.4% in average), while nona-BDEs and tri- to octa-BDEs only contributed 10% and 8%, respectively. The reductions of the absolute mass concentrations of POPs from W20 were in the order PBDEs >> PBDD/Fs > PCDD/Fs ≈ PCBs for all multi-component diesel blends. The reduction fractions of POPs were in the order PCDD/F > PCB ≈ PBDD/F > PBDE, and those of TEQ were PCDD/F > PCB > PBDD/F. Thus, the addition of butanol and acetone, whether pure or hydrous, could further lower the POP emissions from W20.
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characteristics of persistent organic pollutant emissions from a diesel engine generator fueled using blends of waste cooking oil based biodiesel and fossil diesel
Aerosol and Air Quality Research, 2016Co-Authors: Jenhsiung Tsai, Shuijen Chen, Guoping Changchien, Kuolin Huang, Chienwei Feng, Hotsang HuangAbstract:ABSTRACTThis study elucidates the characteristics of persistent organic pollutants (POPs), including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyl (PCBs), polybrominated dibenzo-p-dioxins and polybrominated dibenzofurans (PBDD/Fs) and polybrominated diphenyl ethers (PBDEs), that are emitted from a generator (non-road diesel engine) that is fueled with a blend of waste cooking oil biodiesels (WCO-biodiesels). Experimental results reveal that the mass concentrations of PCDD/Fs, PCBs, PBDD/Fs and PBDEs from the diesel generator that is fueled with petroleum diesel (D100) under loads of 1.5 kW and 3.0 kW were 583–875 pg Nm–3, 580–810 pg Nm–3, 982–1408 pg Nm–3, and 134–216 ng Nm–3, respectively, while the toxicity concentrations of PCDD/Fs, PCBs, and PBDD/Fs were 33.2–58.6, 2.72–3.11, and 1.54–2.30 pg WHO2005-TEQ Nm–3, respectively. W20 and W40 emitted 15–65% and 23–85% less of these POPs by mass (and 25–47% and 46–91% by toxicity), respectively. Among the tested fuel blends, the W40 exhibited the greatest emission factor reductions of mass and toxicity of these four POPs, despite of the load. Therefore, WCO-biodiesels can feasibly be used as an alternative generator fuel, favoring the recycling/reuse of waste oils and mitigating hazards to human health and environment.
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utilization and improvement of the adsorption method for sampling PCDD fs from a sinter plant
Aerosol and Air Quality Research, 2015Co-Authors: Maosung Wang, Guoping Changchien, Lin-chi Wang, Sheng-lun Lin, Chia Yang ChenAbstract:ABSTRACTIn this work, the Adsorption Method for Sampling (AMESA) is developed to collect long-term samples of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from stacks. However, the variation of in duration might affect the analytical results due to the memory effect in the AMESA. This research is one of the very few reports of using AMESA in sinter plants. Eight long-term AMESA (LA) samples were collected, followed by 16 parallel short-term AMESA (SA) and manual (SM) samples. The LA reports good correlations (R = 0.82–0.83) between PCDD/F emissions and the recovery feedstock, which can be further used for emission reduction. However, the breakthrough effects of the highly chlorinated PCDD/Fs is in the range of 6–14% in LA samples, and these are further improved by increasing the glass wool and adsorbent (with higher specific surface area, lower pore size, and higher polarity) packing, and finally reduced to 5.17%. For the short-term sampling, a maximum difference of 170% occurred between SA and SM, if the sampling strategy suddenly changed from LA to SA. The PCDD/F memory effect remained for the first 8 SA samples, with the dominant 1,2,3,4,6,7,8-HPCDD and OCDD. Therefore, five post-washings for the AMESA system took place to successfully reduce the PCDD/F residual mass to > 0.2% of a normal LA. Unfortunately, these residuals were still equal to 51.4% of a normal SA. Therefore, it is not suggested that AMESA replace the current manual sampling method without any modification. According to this study, both the breakthrough and memory effects could be inhibited. Finally, a new inspection system, including both AMESA and short-term samples, is then proposed for improving the PCDD/F control strategy in Taiwan.
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determination of levels of persistent organic pollutants PCDD fs pbdd fs pbdes pcbs and pbbs in atmosphere near a municipal solid waste incinerator
Chemosphere, 2010Co-Authors: Maosung Wang, Jenhsiung Tsai, Shuijen Chen, Guoping Changchien, Kuolin Huang, Yichieh Lai, Wenyinn Lin, Kuoching Chang, Jiatwu LeeAbstract:Abstract This work develops a comprehensive approach for quantitatively analyzing polychlorinated and polybrominated dibenzo- p -dioxins (PCDDs/PBDDs), dibenzofurans (PCDFs/PBDFs), biphenyls (PCBs/PBBs) and diphenyl ethers (PBDEs). This technique, based on multiple (silica, alumina, and active carbon) columns, can be applied to prepare samples for determining the five group compounds based on high-resolution gas chromatography/high-resolution mass spectrometry. The method was also validated by analyses of blank and spiked samples. In the sampled air, the mean PCDD/F, PCB, PBDD/F, PBDE, and PBB concentrations were 59.6 fg WHO-TEQ N m −3 , 6.74 fg WHO-TEQ N m −3 , 12.2 fg WHO-TEQ N m −3 , 52 100 fg N m −3 , and 341 fg N m −3 , respectively. The WHO-TEQ of dioxin-like PCB and PBDD/Fs counted for 8.9% and 16% of total TEQ (summed over PCDD/Fs, PBDD/Fs, and dioxin-like PCBs), respectively, suggesting that the atmospheric concentrations of dioxin and dioxin-like compounds should be regulated together because of the persistence and toxicity of PBDD/Fs and dioxin-like PCBs.
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evaluation of the emission characteristics of PCDD fs from electric arc furnaces
Chemosphere, 2006Co-Authors: Moo Been Chang, Kai Hsien Chi, Hung Chi Huang, Shian Sheng Tsai, Guoping ChangchienAbstract:Abstract Distribution of PCDD/F (polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran) congeners at two electric arc furnaces (EAFs) in Taiwan is evaluated via intensive stack sampling and analysis. Two kinds of exhaust system in EAFs including stack system and shutter system are selected for measuring dioxin emissions. In addition, dioxin emissions during oxidation and reduction stages at EAF-A were characterized. Results indicate that the PCDD/F concentration of stack gas in EAF-A was 4.39 ng/N m3 while total Toxic Equivalent Quantity (TEQ) concentration was 0.35 ng I-TEQ/N m3. The PCDD/F concentration of stack gas in EAF-B was 2.20 ng/N m3 and the TEQ concentration was 0.14 ng I-TEQ/N m3. 1,2,3,4,6,7,8-HpCDF, OCDD and OCDF are the major contributors of the dioxin concentrations for two EAFs investigated and the percentage of PCDD/F in particulate phase increases as the chlorination level of the PCDD/F congener increases. The results obtained on gas/particulate partitioning of PCDD/Fs in flue gases prior to the APCD in EAFs indicate that more than 90% exists in particulate phase. In EAF-A, the PCDD/F concentration during oxidation stage is slightly higher than that measured during reduction stage, including the sampling points of CO converter outlet, prior to bag filter and stack. Majority of PCDD/Fs emitted from steel-making processes exists in particulate-phase (about 60–70%) at both EAFs investigated.
Ruth E. Alcock - One of the best experts on this subject based on the ideXlab platform.
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pentachlorophenol pcp and chloranil as PCDD f sources to sewage sludge and sludge amended soils in the uk
Chemosphere, 1997Co-Authors: Ruth E. Alcock, Kevin C. JonesAbstract:Pentachlorophenol (PCP) and its derivatives (NaPCP and PCPL) contain PCDD/Fs (predominantly Hp-CDD/Fs and OCDD/F) as impurities. Reported concentrations of 2,3,7,8-substituted congeners in technical PCP (1000 – 3000 μg TEQ/kg) are significantly higher than those reported in PCP products such as NaPCP (84 – 510 μg TEQ/kg). PCP-based textile preservatives (particularly associated with imported cotton textiles) probably represent an important PCDD/F source to sewage sludge. Chloranil and chloranil-based dyes and pigments can contain significant levels of PCDD/F impurities as predominantly OCDD. Associated dyes and pigment contain lower PCDD/F concentrations (2 – 200 μg TEQ/kg) than pure chloranil (300 – 2900 μg TEQ/kg). The use of water-based textile dyes containing chloranil in a given catchment could represent a significant source of higher molecular weight PCDD/F congeners to the resulting sewage sludge. In addition to sewage sludge, application of other types of organic amendments (e.g. farm yard manure), paper waste sludge and textile waste could represent important sources of PCDD/Fs to agricultural soils in the UK.
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Pentachlorophenol (PCP) and chloranil as PCDD/F sources to sewage sludge and sludge amended soils in the UK
Chemosphere, 1997Co-Authors: Ruth E. Alcock, Kevin C. JonesAbstract:Pentachlorophenol (PCP) and its derivatives (NaPCP and PCPL) contain PCDD/Fs (predominantly Hp-CDD/Fs and OCDD/F) as impurities. Reported concentrations of 2,3,7,8-substituted congeners in technical PCP (1000 – 3000 μg TEQ/kg) are significantly higher than those reported in PCP products such as NaPCP (84 – 510 μg TEQ/kg). PCP-based textile preservatives (particularly associated with imported cotton textiles) probably represent an important PCDD/F source to sewage sludge. Chloranil and chloranil-based dyes and pigments can contain significant levels of PCDD/F impurities as predominantly OCDD. Associated dyes and pigment contain lower PCDD/F concentrations (2 – 200 μg TEQ/kg) than pure chloranil (300 – 2900 μg TEQ/kg). The use of water-based textile dyes containing chloranil in a given catchment could represent a significant source of higher molecular weight PCDD/F congeners to the resulting sewage sludge. In addition to sewage sludge, application of other types of organic amendments (e.g. farm yard manure), paper waste sludge and textile waste could represent important sources of PCDD/Fs to agricultural soils in the UK.
Jenhsiung Tsai - One of the best experts on this subject based on the ideXlab platform.
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persistent organic pollutant reductions from a diesel engine generator fueled with waste cooking oil based biodiesel blended with butanol and acetone
Aerosol and Air Quality Research, 2017Co-Authors: Jenhsiung Tsai, Shuijen Chen, Guoping Changchien, Bocheng Jheng, Kuolin Huang, Jueiyu ChiuAbstract:ABSTRACTThis investigation focuses on the effects on emissions of persistent organic pollutants (POPs) (polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) and polybrominated diphenyl ethers (PBDEs)) from a diesel engine fuelled by 20 vol% waste cooking oil-based biodiesel (W20) blended with various fractions of dehydrate/hydrous butanol (B/B′) and acetone (A/A′). The emission concentrations of the POPs were in the order PBDE ≫ PBDD/F > PCB > PCDD/F, regardless of the blending fuel or engine load. The POP with highest concentration was PBDE, being 2–3 times that of the others. Conversely, the magnitude of emitted toxicity followed the order PCDD/F > PCB ≈ PBDD/F, while PCDD/F emissions had about 10 times the toxicity concentrations of PCBs and PBDD/Fs. Among the dioxin compounds, the emissions of PCDDs represented 46–73% (average 57%) and 50–72% (average 59%) of total PCDD/F mass and toxicity concentrations, respectively, and were which and were thus significantly higher than those of PCDFs. The non-ortho-PCB contributed almost all toxicity (~100%) of 14 dioxin-like-PCBs, even though its contribution in mass was only 9–32% (average 16%) among the congeners. Similarly, PBDFs accounted for ~100% of toxicity of PBDD/Fs. Additionally, deca-BDEs contributed to most of the mass emissions of PBDEs (47.0–90.5%, 82.4% in average), while nona-BDEs and tri- to octa-BDEs only contributed 10% and 8%, respectively. The reductions of the absolute mass concentrations of POPs from W20 were in the order PBDEs >> PBDD/Fs > PCDD/Fs ≈ PCBs for all multi-component diesel blends. The reduction fractions of POPs were in the order PCDD/F > PCB ≈ PBDD/F > PBDE, and those of TEQ were PCDD/F > PCB > PBDD/F. Thus, the addition of butanol and acetone, whether pure or hydrous, could further lower the POP emissions from W20.
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characteristics of persistent organic pollutant emissions from a diesel engine generator fueled using blends of waste cooking oil based biodiesel and fossil diesel
Aerosol and Air Quality Research, 2016Co-Authors: Jenhsiung Tsai, Shuijen Chen, Guoping Changchien, Kuolin Huang, Chienwei Feng, Hotsang HuangAbstract:ABSTRACTThis study elucidates the characteristics of persistent organic pollutants (POPs), including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyl (PCBs), polybrominated dibenzo-p-dioxins and polybrominated dibenzofurans (PBDD/Fs) and polybrominated diphenyl ethers (PBDEs), that are emitted from a generator (non-road diesel engine) that is fueled with a blend of waste cooking oil biodiesels (WCO-biodiesels). Experimental results reveal that the mass concentrations of PCDD/Fs, PCBs, PBDD/Fs and PBDEs from the diesel generator that is fueled with petroleum diesel (D100) under loads of 1.5 kW and 3.0 kW were 583–875 pg Nm–3, 580–810 pg Nm–3, 982–1408 pg Nm–3, and 134–216 ng Nm–3, respectively, while the toxicity concentrations of PCDD/Fs, PCBs, and PBDD/Fs were 33.2–58.6, 2.72–3.11, and 1.54–2.30 pg WHO2005-TEQ Nm–3, respectively. W20 and W40 emitted 15–65% and 23–85% less of these POPs by mass (and 25–47% and 46–91% by toxicity), respectively. Among the tested fuel blends, the W40 exhibited the greatest emission factor reductions of mass and toxicity of these four POPs, despite of the load. Therefore, WCO-biodiesels can feasibly be used as an alternative generator fuel, favoring the recycling/reuse of waste oils and mitigating hazards to human health and environment.
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determination of levels of persistent organic pollutants PCDD fs pbdd fs pbdes pcbs and pbbs in atmosphere near a municipal solid waste incinerator
Chemosphere, 2010Co-Authors: Maosung Wang, Jenhsiung Tsai, Shuijen Chen, Guoping Changchien, Kuolin Huang, Yichieh Lai, Wenyinn Lin, Kuoching Chang, Jiatwu LeeAbstract:Abstract This work develops a comprehensive approach for quantitatively analyzing polychlorinated and polybrominated dibenzo- p -dioxins (PCDDs/PBDDs), dibenzofurans (PCDFs/PBDFs), biphenyls (PCBs/PBBs) and diphenyl ethers (PBDEs). This technique, based on multiple (silica, alumina, and active carbon) columns, can be applied to prepare samples for determining the five group compounds based on high-resolution gas chromatography/high-resolution mass spectrometry. The method was also validated by analyses of blank and spiked samples. In the sampled air, the mean PCDD/F, PCB, PBDD/F, PBDE, and PBB concentrations were 59.6 fg WHO-TEQ N m −3 , 6.74 fg WHO-TEQ N m −3 , 12.2 fg WHO-TEQ N m −3 , 52 100 fg N m −3 , and 341 fg N m −3 , respectively. The WHO-TEQ of dioxin-like PCB and PBDD/Fs counted for 8.9% and 16% of total TEQ (summed over PCDD/Fs, PBDD/Fs, and dioxin-like PCBs), respectively, suggesting that the atmospheric concentrations of dioxin and dioxin-like compounds should be regulated together because of the persistence and toxicity of PBDD/Fs and dioxin-like PCBs.
Kai Hsien Chi - One of the best experts on this subject based on the ideXlab platform.
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Sources identification of PCDD/Fs in soil and atmospheric deposition in Taiwan.
Chemosphere, 2018Co-Authors: Tuan Hung Ngo, Yuan-wu Chen, Han Hsing Tsou, Ya Fang Chen, Kai Hsien ChiAbstract:Abstract PCDD/Fs are among pollutants, which gain major concern from Taiwan government and citizens during industrialization. PCDD/Fs can be emitted into the atmosphere, soil, and water environment in either vapor or solid forms. Atmospheric deposition is the main pathways for atmospheric PCDD/Fs to precipitate on surface soil. In this study, a simultaneous analysis of both soil and deposition PCDD/Fs was done to investigate the relationship between in-soil and deposited PCDD/Fs in Taiwan. Soil samples (n = 84) and atmospheric deposition samples (n = 57) were collected within overlapped periods of time. Geometric mean of 10.4 pg WHO-TEQ/g was found in the soil samples when the geometric mean of atmospheric deposited PCDD/F concentrations was found to be 7.39 pg WHO-TEQ/m2/day. Concentration of PCDD/Fs in samples collected in industrial location were higher than those collected in other locations in all sampling areas. OCDD, OCDF, HPCDD, HpCDF, were the predominant congeners in PCDD/F profile in both soil and atmospheric deposited samples, when 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF were major contributors for PCDD/F fingerprint with WHO-TEQ transformation. Positive Matrix Factorization (PMF) analysis showed that 83% of soil PCDD/Fs correlate with atmospheric deposition process originated from industrial activities (44%) and long range transport activities (39%). Furthermore, the PMF analysis found long range transport, municipal solid water incinerators (MSWIs), industrial waste incinerators (IWIs), electric arc furnace, recycling process of aluminum, sintering plants to be the main sources contributing to atmospheric deposited PCDD/Fs.
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innovative PCDD f containing gas stream generating system applied in catalytic decomposition of gaseous dioxins over v2o5 wo3 tio2 based catalysts
Chemosphere, 2008Co-Authors: Chia Cheng Yang, Kai Hsien Chi, Shu Hao Chang, Bao Zhen Hong, Moo Been ChangAbstract:Abstract Development of effective PCDD/F (polychlorinated dibenzo- p -dioxin and dibenzofuran) control technologies is essential for environmental engineers and researchers. In this study, a PCDD/F-containing gas stream generating system was developed to investigate the efficiency and effectiveness of innovative PCDD/F control technologies. The system designed and constructed can stably generate the gas stream with the PCDD/F concentration ranging from 1.0 to 100 ng TEQ N m −3 while reproducibility test indicates that the PCDD/F recovery efficiencies are between 93% and 112%. This new PCDD/F-containing gas stream generating device is first applied in the investigation of the catalytic PCDD/F control technology. The catalytic decomposition of PCDD/Fs was evaluated with two types of commercial V 2 O 5 –WO 3 /TiO 2 -based catalysts (catalyst A and catalyst B) at controlled temperature, water vapor content, and space velocity. 84% and 91% PCDD/F destruction efficiencies are achieved with catalysts A and B, respectively, at 280 °C with the space velocity of 5000 h −1 . The results also indicate that the presence of water vapor inhibits PCDD/F decomposition due to its competition with PCDD/F molecules for adsorption on the active vanadia sites for both catalysts. In addition, this study combined integral reaction and Mars–Van Krevelen model to calculate the activation energies of OCDD and OCDF decomposition. The activation energies of OCDD and OCDF decomposition via catalysis are calculated as 24.8 kJ mol −1 and 25.2 kJ mol −1 , respectively.
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evaluation of the emission characteristics of PCDD fs from electric arc furnaces
Chemosphere, 2006Co-Authors: Moo Been Chang, Kai Hsien Chi, Hung Chi Huang, Shian Sheng Tsai, Guoping ChangchienAbstract:Abstract Distribution of PCDD/F (polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran) congeners at two electric arc furnaces (EAFs) in Taiwan is evaluated via intensive stack sampling and analysis. Two kinds of exhaust system in EAFs including stack system and shutter system are selected for measuring dioxin emissions. In addition, dioxin emissions during oxidation and reduction stages at EAF-A were characterized. Results indicate that the PCDD/F concentration of stack gas in EAF-A was 4.39 ng/N m3 while total Toxic Equivalent Quantity (TEQ) concentration was 0.35 ng I-TEQ/N m3. The PCDD/F concentration of stack gas in EAF-B was 2.20 ng/N m3 and the TEQ concentration was 0.14 ng I-TEQ/N m3. 1,2,3,4,6,7,8-HpCDF, OCDD and OCDF are the major contributors of the dioxin concentrations for two EAFs investigated and the percentage of PCDD/F in particulate phase increases as the chlorination level of the PCDD/F congener increases. The results obtained on gas/particulate partitioning of PCDD/Fs in flue gases prior to the APCD in EAFs indicate that more than 90% exists in particulate phase. In EAF-A, the PCDD/F concentration during oxidation stage is slightly higher than that measured during reduction stage, including the sampling points of CO converter outlet, prior to bag filter and stack. Majority of PCDD/Fs emitted from steel-making processes exists in particulate-phase (about 60–70%) at both EAFs investigated.
