PROCEEDINGS OF THE COMBUSTION INSTITUTE
·
2022
·
IF 6.535
Yongda Huang,Hongyun Hu,Chan Zou,Huimin Liu,Shuai Li,Xiaojiang Wu,Lejin Xu,Hong Yao
The partitioning of selenium in coal-fired flue gas and desulfurization wastewater is of great threat to the ecological environment and human health. However, the unclear understanding of interactions between selenium vapors and fly ash hinders the emission control of selenium from coal-fired power plants. To further illuminate the mechanism of selenium partitioning and transformation, this study carefully estimated selenium distribution characteristics in the coal combustion byproducts from several industrial power plants. The effective temperature range as well as the key ash components for selenium retention by fly ash was clarified by multiple-scale experiments and theoretical perspectives. The results showed that gaseous selenium tended to be captured by fly ash at a medium-to-low temperature range (i.e. below 650 °C). The limited residence time resulted in the incomplete capture of gaseous selenium by fly ash. Mullite , quartz, iron oxides , and anhydrite in fly ash were found to be the main trappers for gaseous selenium. Among these components, iron oxides showed excellent selenium adsorption performance at a wide temperature range of 150-700 °C, which was realized by the strong chemical adsorption . By contrast, as the dominant phases in fly ash for the physical adsorption of gaseous selenium, mullite and quartz mainly captured gaseous selenium below 300 °C. On the other hand, sulfur dioxides had priority over gaseous selenium to react with calcium-containing ash components by forming anhydrite in the high-temperature region. The formed anhydrite had a limited selenium adsorption capacity , which was confirmed to capture gaseous selenium through a combination of physical adsorption and weak chemical adsorption. For the in-depth control of selenium emitted into desulfurization system and atmosphere environment, these findings provided a comprehensive insight into the behavior of selenium partitioning and transformation into fly ash during coal combustion.
研究领域:
环境科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Rihong Xiao,Yili Zhang,Shuzhou Wei,Xing Chuai,Xiangzheng Cui,Zhuo Xiong,Junying Zhang,Yongchun Zhao
Massive Hg emissions from coal-fired units cause serious environmental pollution and result in a substantial waste of Hg resources. In this study, the prepared millimeter-grade Se/SiO 2 adsorbent was applied as a filler to adsorb mercury in a fixed-bed reactor to obtain the high value-added product HgSe, which solved the problem of short contact time and secondary pollution caused by the traditional injection mercury removal adsorbents. Experimental Hg removal showed that the 25 % Se-loaded adsorbent exhibited excellent Hg removal performance at 150 °C, with a saturation adsorption capacity of mercury was as high as 101.04 mg/g, nearly 300 times that of commercial activated carbons. Additionally, the influence of the flue gas composition on the Hg removal performance of Se/SiO 2 was studied. The results showed that O 2 , NO, and HCl increased the efficiency of Hg removal and SO 2 and SO 3 had trivial impact on the Hg removal performance. The Hg temperature-programmed desorption test results showed that the adsorbed Hg appeared predominantly as HgSe on the sample surface. DFT calculations verified that Se loading improved Hg removal performance and defined the adsorption mechanism. Moreover, the prepared Se/SiO 2 adsorbent carrier was soluble SiO 2 , which provided a good condition for the subsequent high-purity collection of HgSe. Finally, the technological process of Hg removal via Se-loaded adsorbents and the recovery of HgSe were proposed, which could offer a new way to achieve the resource utilization of Hg.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
·
2024
·
IF 1.6
Muhammad Sarfraz,Yang Li,He Yang,Lijun Jin,Haoquan Hu
Mercury (Hg 0 ) emission from coal-fired industrial plants poses severe threats to ecosystem sustainability and human health, urging the development of novel and cost-effective adsorbents to treat industrial flue gas. Herein, the modification of industrial residual red mud (RM) through the impregnation of hydrogen halides (HH) and its adsorption characteristics for removing elemental mercury from combustion flue gas was reported. Experimental investigation of HH-modified RM reveals that the hydrogen iodide (HI)-modified RM with a concentration of 1.5 M had a maximum Hg 0 removal efficiency of 98%, whereas hydrogen bromide (HBr) 1.5 M modified RM had a maximum Hg 0 removal efficiency of 90%. The effect of various parameters, such as reaction temperature and halide concentrations, were also found to be influential for the adsorption efficiency of the modified RM. Moreover, it is important to highlight the chemisorption characteristics of HI-modified RM, which significantly enhances the efficiency of the removal process. The Hg 0 removal efficiency increases with the increase in HI concentration (1.5 M @ 93%) with an optimal reaction temperature of 140°C. Furthermore, the maximum Hg 0 removal attained with a change in NO concentration was 98% at 200 ppm. However, increasing the SO 2 concentration reduces the efficiency of RM for removing Hg 0 in simulated coal combustion flue gas. The pseudo-second-order model ( R 2 = 0.98) accurately describes the adsorption of in kinetic investigations, indicating a chemisorption mechanism. This analysis of the chemisorption mechanism highlights the efficiency of halide-modified industrial solid waste, which has the potential to be used in the design of economical and innovative adsorbents for reducing environmental pollution. The present study employed specific reaction parameters such as reaction temperature, halide loading contents, and different flue gas compositions, which had not been extensively explored.
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2016
·
IF 3.611
Shunlin Tang,Lina Wang,Xinbin Feng,Zhaohui Feng,Ruiyang Li,Huipeng Fan,Ke Li
Mercury species distribution in the flue gas from three typical coal-fired power plants have been investigated using a C-5000 sampler for Ontario Hydro Method (OHM) to evaluate specified Hg emission inventories in the largest coal-production province of China, Inner Mongolia. The feed coal, bottom ash, fly ash and gypsum have also been sampled in the field. Mercury emissions are in the dominant form of Hg 0 (>85%). The Hg 2+ (<15%) and the Hg p (<2%) emissions are minor fractions of Hg t in the flue gas. The wet limestone flue gas desulfurization device (WLFGD) showed much higher removal efficiency for Hg 2+ (87–95%) than for the other two Hg species. The input Hg/output Hg varied from 92% to 115% for the tested 3 coal-fried utility boilers during sampling time. We obtained comprehensive Hg discharge factors, including direct atmospheric Hg emission factors and indirect discharge factors of Hg associated with bottom ash, fly ash and gypsum, to the environment, designating the fates of Hg in coal. We estimated the Hg discharges from coal-fired power plants in Inner Mongolia in 2008–2014 and expanded to China. The maximum of direct Hg emissions from coal-fired power plants of Inner Mongolia was 24 Mg in 2012. The Chinese coal-fired power plants emitted directly 100 Mg Hg to the atmosphere every year at the nationwide air control actions. The maximum discharges of Hg associated with fly ash and gypsum of Inner Mongolia was 81 Mg and 11 Mg in 2012, respectively. The national Hg discharges with fly ash and gypsum every year are respectively about 300 Mg and 82 Mg, majority of which may be reemitted to the atmosphere by the utilization industry. Therefore, mercury emissions from coal-fired power plants are not the largest single source of Hg to the atmosphere in normal operation of the current efficient denitrification, particles control and desulfurization devices. Instead, the utilization industry of fly ash and gypsum would be emitting more Hg to the atmosphere.
研究领域:
环境科学
·
能源与动力工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2018
·
IF 0
Zequn Yang,Hailong Li,Chen Liao,Jiexia Zhao,Shihao Feng,Pu Li,Xi Liu,Jianping Yang,Kaimin Shih
Rattle-type Fe3O4@CuS synthesized using a two-step method was applied for elemental mercury (Hg0) adsorption in coal combustion flue gas for the first time. The Fe3O4 with strong magnetization was an ideal candidate as a core to make the sorbent recyclable, while the stabilized ultrathin CuS shell assured that the Fe3O4@CuS had a higher Brunauer–Emmett–Teller (BET) surface area with more exposed active sites and stronger magnetization. The optimal operating temperature of 75 °C allowed for the injection of the sorbent between the wet desulfurization (WFGD) and wet electrostatic precipitator (WESP), which removed the detrimental influence of nitrogen oxides. Simulated flue gas (SFG) in this section showed a slight inhibitive effect on Hg0 adsorption over the Fe3O4@CuS, mainly due to the presence of water vapor (H2O). The inhibition of H2O was proven to be the result of an active site prevention effect instead of the widely recognized competitive adsorption effect. The adsorption capacity and rate of the Fe3O4@CuS for Hg0 capture reached 80.73 mg g–1 and 13.22 μg (g min)−1, which were the highest values among the magnetic sorbents currently reported for Hg0 removal from coal combustion flue gas. These properties allowed the sorbent to maintain a 100% Hg0 capture efficiency for more than 20 h with only a 50 mg dosage when no regeneration step was applied. Meanwhile, the contacting time between the sorbent and Hg0 was generally less than 5 s in a typical sorbent injection process. Polysulfides dominated the capturing process and primarily contributed to the extremely high adsorption capacity/rate. A multistep reaction mechanism was proposed to explain the Hg0 adsorption over Fe3O4@CuS. At the first stage, polysulfide participated in Hg0 adsorption as the most active component and was consumed rapidly. After that, S–S dimers, sulfides, and even copper-terminated sites functioned as the adsorption centers. The as-formed mercury–copper (Hg–Cu) amalgam was transformed into mercury sulfide (HgS), a process that was dependent on the extent of the saturation of sulfide sites. With these advantages, Fe3O4@CuS is a promising, cost-effective, highly recyclable, and efficient alternative to the traditional activated carbon for capturing Hg0 in coal combustion flue gases.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
Journal of Environmental Sciences
·
2024
·
IF 5.9
Lin Zhang,Yang Zheng,Guoliang Li,Jiajia Gao,Yali Tong,Tao Yue
With the rapid development of adsorbents for removal of elemental mercury (Hg 0 ) from coal combustion flue gas, the preparation of adsorbents with superior performance, lower cost and environmental friendliness remains an important challenge. An incipient wetness impregnation method followed by in-situ selenization was used to load copper selenide (CuSe) onto the surface of optimal magnetic biochar (OMBC). The results showed that CuSe significantly enhanced the Hg 0 removal performance of the OMBC, and CuSe loading ratio of 10 % (10CuSe/OMBC) had the best Hg 0 removal performance. 10CuSe/OMBC maintained its Hg 0 removal efficiency above 95 % for 150 min at 30∼150 °C, and it had a good resistance to SO 2 . The equilibrium adsorption capacity of 10CuSe/OMBC could reach up to 8.73 mg/g, which was close to the theoretical value 12.99 mg/g, and the adsorption rate was up to 20.33 µg/(g·min) Meanwhile, 10CuSe/OMBC had strong magnetism that is not permanently magnetized, which could be separated from desulfurization gypsum and recycled many times. Characterization results demonstrated that Se 2 2- , Cu 2+ and O β played essential roles in the oxidation of Hg 0 , and Se 2 2- and Se 2- can immobilize Hg 2+ to HgSe. 10CuSe/OMBC has important guiding significance for practical application because of its low cost, high performance and low mercury leaching characteristic to form HgSe.
研究领域:
环境科学
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材料科学
✓ 已验证
DOI
高影响因子
Journal of Environmental Sciences
·
2024
·
IF 5.9
Yafei Xia,Ting Gao,Yuhui Liu,Meng Qi,Jian-Ming Zhu,Hui Tong,Yiwen Lv,Chengshuai Liu
Coal power plants annually generate quantities of byproducts that release environmentally hazardous heavy metals like Cd and Pb. Understanding the behavior and spatiotemporal impacts on soils of these releases is crucial for pollution control. This study investigated the concentrations and isotope ratios of Cd/Pb in combustion byproducts, depositions and soils collected from a coal-fired power plant or its surrounding area. The pulverized fuel ash (PFA) and desulfurized gypsum (DG) exhibited heavier Cd isotopes with Δ 114 Cd values of 0.304‰ and 0.269‰, respectively, while bottom ash (BA) showed lighter Cd isotopes (Δ 114 Cd BA-coal = –0.078‰), compared to feed coal. We proposed a two-stage condensation process that governs the distribution of Cd/Pb, including accumulation on PFA and DG within electrostatic precipitators and desulfurization unit, as well as condensation onto fine particles upon release from the stack. Emissions from combustion and large-scale transport make a significant contribution to deposition, while the dispersion of Cd/Pb in deposition is primarily influenced by the prevailing wind patterns. However, the distribution of Cd/Pb in soils not only exhibit predominant wind control but is also potentially influenced by the resuspension of long-term storage byproducts. The power plant significantly contributes to soil in the NW–N–NE directions, even at a considerable distance (66%–79%), demonstrating its pervasive impact on remote regions along these orientations. Additionally, based on the vertical behavior in the profile, we have identified that Cd tends to migrate downward through leaching, while variations in Pb respond to the historical progression of dust removal.
研究领域:
环境科学
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地球化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2021
·Vol. 29
·期 17
·24612-24622
·
IF 4.223
Li Zhansheng,Zhao Hongxia,Li Xintong,Bekele Tadiyose Girma
Environmentally persistent free radicals (EPFRs) are an emerging class of environmental hazardous contaminants that extensively, stably exist in airborne particulate matter and pose harmful effects on human health. However, there was little research about the sources of EPFRs in actual atmospheric conditions. This study reported the occurrence, characteristics, and sources of EPFRs and polycyclic aromatic hydrocarbons (PAHs) in PM 2.5 collected in Dalian, China. The concentrations of PM 2.5 -bound EPFRs ranged from 1.13 × 10 13 to 8.97 × 10 15 spins/m 3 (mean value: 1.14 × 10 15 spins/m 3 ). Carbon-centered radicals and carbon-centered radicals with adjacent oxygen atoms were detected. The concentration of ∑PAHs ranged from 1.09 to 76.24 ng/m 3 , and PAHs with high molecular weight (HMW) were predominant species in PM 2.5 . Correlation of EPFRs with SO 2 , NO 2 , O 3 , and 12 kinds of PAHs indicated that both fuel (coal and biomass) combustion and photoreaction in atmosphere influenced the concentrations of EPFR. The positive matrix factorization (PMF) model results have shown that the primary sources contributed most of the EPFRs and those of secondary sources had a little proportion. Coal combustion (52.4%) was the primary contributor of EPFRs, followed by traffic emission (22.6%), industrial sources (9.6%), and secondary sources (9.2%) during the heating period, whereas industrial emission (39.2%) was the primary contributor, followed by coal combustion (38.1%), vehicular exhaust (23.5%), and secondary sources (9.6%) during the non-heating period. The finding of the present study provides an important evidence for further study on the formation mechanism of EPFRs in actual atmospheric to control the air pollution.
研究领域:
环境科学
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公共卫生
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大气化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Shengyan Liu,Wensheng Lin,Ao Wang,Wei Chen,Liangying Yu,Chong Tian
The mass discharge of mercury from coal-fired power plant has caused great harm, abating mercury emissions is of preoccupation for protecting public environmental safety and human health. Metal oxides are often used for Hg 0 removal in the flue gas. In this paper, a hollow tubular MnO x (MnCot) was successfully prepared by rapid flame annealing using cotton fiber as a sacrificial template. The MnCot were then well characterized and tested for its capability for Hg 0 removal in flue gas. The results indicate that the flame assisted synthesis method for rapidly prototyping metal oxides with typical structures is achievable. The hollow tubular structure of the cotton fiber is well reprinted with good crystallization of Mn 3 O 4 . The inner diameter of the hollow tubular MnCot is about 10 μm, and the thickness of the tube is about 1 μm. The Hg 0 removal efficiency on MnCot can be maintained as high as 90 % under simulated flue gas atmosphere below 240°C. O 2 and NO have a positive effect on the Hg 0 removal, which can act as the fresh active sits thus enhancing its capability for Hg 0 removal. However, the presence of SO 2 will result in the surface sulfation on MnCot, thus deteriorating its capability for Hg 0 removal. Further, the competitive adsorption between SO 2 and Hg 0 on the material will also weaken its capability for Hg 0 removal. The hollow tubular MnO x rapidly prepared by one-step flame annealing has a good industrial application potential for Hg 0 removal in coal-fired flue gas.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2020
·
IF 5.778
Xiaolong Yao,Ke Wang,Wan Wang,Tingting Zhang,Wei Wang,Xiaoyang Yang,Feng Qian,Hailong Li
Household coal combustion is identified to be the second largest emission source of polycyclic aromatic hydrocarbons (PAHs) in China. In this study, ferroferric oxide (Fe 3 O 4 ) was used as a coal burning additive to reduce PAHs emission from coal combustion in a household coal stove. The results showed that Fe 3 O 4 participated in the coal combustion process. The addition of Fe 3 O 4 reduced the release of PAHs during the coal combustion process, and could improve the residence capacity of ash residue to these PAHs. Toxic equivalent quantity (TEQ) of PAHs in flue gas from combustion of coal mixed with Fe 3 O 4 was less than that from the raw coal combustion. For a typical combustion temperature of 850 °C, the TEQ of PAHs for the mixture of coal and 2.0 wt % Fe 3 O 4 decreased 21.98% compared to that for the raw coal. The abundant active surface oxygen species originated from the phase transformation of iron oxides probably accelerated the cracking of PAHs, and hence led to the reduction of PAH emissions and their TEQ. The study could help to develop new technology for reduction of PAHs emission from household coal combustion.
研究领域:
环境科学
·
能源与燃料
·
化学工程
✓ 已验证
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2017
·
IF 3.752
Tiantian Cao,Zijian Zhou,Qian Chen,Zhen Li,Shengming Xu,Jianlong Wang,Minghou Xu,Teresa Bisson,Zhenghe Xu
A novel class of magnetically responsive catalytic sorbents are proposed and synthesized with a potential application to simultaneous removal of Hg 0 and NO at low temperature from the flue gases of coal-fired power plants. The catalytic sorbent consists of magnetite (Fe 3 O 4 ), molecular sieve (HZSM-5), supported silver nanoparticles and catalytically reactive component of V 2 O 5 . Each of these materials provides a unique function for the purpose of capturing mercury, removing NO, and separation from fly ash. After separation from the fly ash, the spent sorbent can be regenerated and reused, leaving an uncontaminated fly ash product. The successful synthesis as designed was confirmed and properties of the catalytic sorbent were characterized by several methods. The synthesized catalytic sorbent was able to completely capture Hg 0 at 150 °C with a capture capacity as high as 32.4 μg·g −1 , while achieving 84% removal of NO at 150 °C. Even at a relatively high space velocity, the catalytic sorbent achieved 97% Hg 0 and 80% NO removal simultaneously, while maintaining a good stability after repetitive regeneration and recycle. The magnetically responsive catalytic composite was shown to be a promising candidate for multi-pollutant emission control from coal-fired power plants.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL TECHNOLOGY
·
2020
·
IF 2.213
Shengcai Wang,Zequn Yang,Jiexia Zhao,Hailong Li,Jianping Yang,Jianfei Song,Xueyi Guo
Developing efficient sorbents with rapid kinetics is the main challenge encountered for Hg0 capture from coal combustion flue gas in a sorbent injection scenario. Binary mineral sulfide-based materials combining copper sulfide (CuS) and zinc sulfide (ZnS) to exert their capabilities for Hg0 capture at the low- and high-temperature was for the first time reported for Hg0 removal to realize a wide temperature range sorbents. When the molar ratio between CuS and ZnS was 10%, the as-synthesized 10Cu-Zn nanocomposite exhibited excellent Hg0 uptake rate at 150°C that could degrade 40 μg/m3 of Hg0 to undetectable level at the end of a 60-s experiment with the dosage of only 1 mg. This Hg0 uptake rate is folds higher compared to that when bare CuS or ZnS was adopted alone at this specific temperature. The typical flue gas atmospheres had negligible effect on Hg0 removal over 10Cu-Zn in a short contact time, which further suggests that the binary sorbents were proper to be injected before the electrostatic precipitator system. Moreover, it is found that, by adjusting the ratio between CuS and ZnS, it is potential to develop binary sorbent suiting any temperature conditions that may achieve an exceedingly high Hg0 capture performance. Thus, this work not only justified the candidature of 10Cu-Zn as a promising alternative to traditional activated carbon for Hg0 capture from coal combustion flue gas but also guided the future development of multi-component mineral sulfide-based sorbents for Hg0 pollution remediation from various industrial flue gases.
研究领域:
环境科学
·
大气污染控制
·
材料科学
·
化学工程
·
能源工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）