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
TALANTA
·
2024
·
IF 5.6
Yukun Huang,Guangyu Chen,Biao Fu,Yingfu Si,Peng Li,Yijun Cao,Lingkun Rong,Chunjie Zhao
This study developed a rapid and efficient graphite furnace digestion combined with inductively coupled plasma emission spectrometry (ICP-OES) method, enabling precise quantification of germanium (Ge) in coal and various coal-derived metallurgical byproducts across a broad concentration level (∼ppm-n%). The graphite furnace digestion conditions were examined intensively as a function of the acid amounts of HNO 3 and HF (5–10 mL), temperature (80–180 °C), time (1–5 h), and acid drive methods (H 3 BO 3 neutralization versus heating). Coal references including SARM 19, SARM 20, NIST SRM 1632e, and fly ash standard NIST SRM 2689 were tested. The optimum recovery of germanium was obtained when the HNO 3 dosage, HF dosage, solid sample mass, temperature, and duration time were 10 mL, 5 mL, 0.1 g, 80 °C and 1 h. Agreement of 95.15–96.54 % between the measured and certified value was obtained under the optimum conditions. The spiked recovery was 103.23–103.54 %, indicating the matrix-analytes interactions were negligible. Boric acid neutralization reduced the recovery rates to 47.2–49.3 % and was not be appropriate for driving HF. The optimal spectral line for determining Ge is at a wavelength of 265.117 nm, at which the limit of detect and the limit of quantification were 0.46 μg L −1 and 1.53 μg L −1 , respectively. The applicability of the method was validated by quantifying Ge in Ge-rich lignite, fly ashes (FA), and chlorinated distillation residue (CR) samples. The concentration of Ge in coals was 44.75–225.41 μg g −1 , the content in FA was 0.68%–2.3 %, and the content in CR was 0.18 %, with the uncertainty of the method obtained being less than 0.5 %. X-ray fluorescence spectrometer (XRF) was used to verify the results. The difference between XRF data and ICP-OES data was less than 5 %, confirming the accuracy and reproductivity of the analytical method.
研究领域:
分析化学
·
环境科学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Siqian Zhang,Cheng Zhang,Qiang Wang,Wha-Seung Ahn
A series of ZSM-5 catalysts were synthesized using fly ash from power plants and red mud from aluminum production in different weight ratios. The ZSM-5 was subsequently coimpregnated with Co and Mn and tested for the low-temperature selective catalytic reduction of NOx by NH3 (NH3-SCR). These catalysts were characterized by XRD, N2-adsorption isotherms, SEM, XPS, and H2-TPR. Among all the prepared catalysts, 5 wt % Co 10 wt % Mn/ZSM-5 had shown the best catalytic activity, with 98.8% conversion of NOx and 90.7% selectivity toward N2 at 150 °C. This is comparable to the performance of a similar ZSM-5 catalyst prepared using chemical reagents. The high ratio of Mn4+/(Mn4+ + Mn3+ + Mn2+) in the catalyst improved the NOx conversion, whereas the moderate redox property imparted by Co3+ led to high N2 selectivity. This catalyst also showed strong resistance against poisoning in 100 ppm SO2 and 5% H2O. This work demonstrates that effective NOx removal treatment with high N2 selectivity and sufficient stability for either cement plants or incinerators can be achieved by using a porous catalyst/support material produced from industrial solid wastes.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2021
·
IF 7.086
Bing Yuan,Hongyun Hu,Yongda Huang,Biao Fu,Huimin Liu,Guangqian Luo,Yongchun Zhao,Hong Yao
Gaseous selenium is of high saturated vapor pressure , making its retention in solid phases quite difficult during coal combustion . The selenium transformation from gaseous form into solid phases at low temperatures can be essential to control selenium emission. To understand the migration of SeO 2 (g) on ash particles in the low-temperature zone, this study investigated the speciation of selenium in fly ash and simulated the physical retention of SeO 2 (g) on fly ash. The results demonstrated that there was a large proportion of physically-bound Se in the fly ash of pulverized-coal-fired boiler (22.62 %–58.03%), while the content of physically-bound Se in fly ash of circulated fluidized-bed boiler was lower (∼6%). The physically-bound Se was formed through selenium condensation and physical adsorption. The decrease of temperature or the increase of cooling rate could promote the transformation of gaseous selenium to solid phase and the presence of HCl might suppress SeO 2 transformation into Se in the condensation process . Meanwhile the compositions of fly ash had a great influence on the selenium adsorption process. Among typical coal-fired ash components, mullite showed the best performance in the selenium capture in the temperature range of 90–200 °C, contributing to the high content of physically-adsorbed selenium in PC fly ash. These findings provided new ideas for improving the removal rate of volatile selenium.
研究领域:
环境科学
·
能源与燃料
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2021
·
IF 10.588
Weiqing Shen,Nengwu Zhu,Yunhao Xi,Junlin Huang,Fei Li,Pingxiao Wu,Zhi Dang
High contents of heavy metals and Cl are major challenges for incineration residue disposal. Classification by the Chinese government and the coronavirus disease 2019 pandemic have changed the characteristics of incineration residues, thereby increasing the difficulty of disposal. In this study, medical waste incineration fly ash (MWI FA) was proposed as an additive to promote chlorination volatilization of heavy metals from municipal solid waste incineration fly ash (MSWI FA) and medical waste incineration slag (MWI S). When the mixing ratio of MWI FA to MSWI FA was 1:3, the chlorination volatilization efficiencies of Cu, Zn, Pb, and Cd at 1000 °C for 60 min were 50.2%, 99.4%, 99.7%, and 97.9%, respectively. When MWI FA was mixed with MWI S at a ratio of 1:1, the chlorination volatilization efficiencies of Cu, Zn, Pb, and Cd at 1200 °C for 40 min were 88.9%, 99.7%, 97.3%, and 100%, respectively. Adding MWI FA can replenish Cl in MSWI FA and MWI S while increasing the surface area and forming pore structures by sublimation of NaCl and decomposition of CaSO 4 , or can reduce the melting point and viscosity by Na 2 O destroying the glass matrix. Therefore, MWI FA can be co-disposed with MSWI FA and MWI S respectively to enhance the chlorination volatilization of heavy metals.
研究领域:
环境科学
·
废弃物处理
✓ 已验证
DOI
PubMed
高影响因子
Journal of Cleaner Production
·
2022
·
IF 11.072
Wenju Tao,Jiaxin Yang,Zhibo Liu,Yifan Zhang,Liyu Chen,Shaohua Wu,Jinbo Qiao,Zhengduo Xue,Zhaowen Wang
The recovery and utilization of by-product coal fly ash (CFA) in high-value-added thermal power plants is of great significance. This research focused on producing high-value-added Al–Si master alloy by aluminothermic reduction with coal fly ash as the raw material. The effects of reduction time and reducing agent amount on thermal reduction products were investigated using the single factor method. X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) results showed that Al, Si, and a small amount of Fe were the main components of the alloy. With an increase in reaction time, the mass fraction of Si in the product increased from 4.41% to 9.93%. Besides, the molten salt after thermal reduction was recovered by the electrochemical reduction process. The results showed that a longer electrolysis time is more conducive to improving the recovery of Si and Al. The results of cyclic voltammetry and electrodeposition showed that Si would be reduced in a multi-step process. Combined with thermal reduction and electrochemical secondary recovery process , the comprehensive recovery of Al and Si in fly ash could reach 87.33% and 84.02%, respectively.
研究领域:
材料科学
·
环境工程
✓ 已验证
DOI
高影响因子
Green Energy & Environment
·
2019
·
IF 0
Ge Li,Baodong Wang,Qi Sun,Wayne Qiang Xu,Ziran Ma,Hongyan Wang,Daojun Zhang,Jiali Zhou
A combined acid–alkali hydrothermal method was used to prepare fly ash –derived SAPO-34 molecular sieves from a thermal power plant in Inner Mongolia (China). The specific surface area of the prepared fly-ash-derived SAPO-34 molecular sieves was 579 m 2 g −1 , the total pore volume was about 0.27 cm 3 g −1 , and the pore size was 0.56 nm; the molar ratios of Al 2 O 3 :P 2 O 5 :SiO 2 were 1:0.86:0.45. Cu/SAPO-34 catalysts were prepared by impregnation of low-cost fly-ash-derived SAPO-34 molecular sieves as a support and tested in selective catalytic reduction with NH 3 (NH 3 -SCR). Powder X-ray diffraction (XRD), N 2 adsorption–desorption, X-ray photoelectron spectroscopy (XPS), H 2 temperature-programmed reduction (H 2 -TPR), NH 3 temperature-programmed desorption (NH 3 -TPD), electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), X-ray fluorescence analysis (XRF) and scanning electron microscopy (SEM) were used for catalyst characterization and investigation of the relationships between the catalyst structure and the catalytic activity. The actual silica:alumina ratio of the molecular sieves did not increase with increasing Cu loading, indicating that increasing the Cu loading does not change the original structure of the SAPO-34 molecular sieves. The XRF and NMR results showed that replacement by Cu results in more Si islands. The molecular sieve acidity decreased because of the increased number of Si islands. The NH 3 -TPD results showed that for the Cu/SAPO-34 catalysts there was a low correlation between the low-temperature activity and the amount of acidic sites. SCR activity is closely related to the location of Cu. The 4.47Cu/SAPO-34 catalyst has the highest isolated Cu 2+ showed the highest NH 3 -SCR activities (> 90%) at 250–350 °C. This work opens up new avenues for recycling fly ash formed in coal-fired power plants (reducing environmental pollution) and developing low-cost SCR catalysts for NO x pollution control.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2024
·
IF 5.9
Chen Li,Chuncai Zhou,Wenwen Li,Wenrui Zhu,Jiaqian Shi,Lei Wu,Guijian Liu
Coal fly ash (CFA) is a promising alternative source for critical elements. Most of the critical elements in CFA are associated with the aluminosilicate glassy phase , which hinders their ability to solubilize during acid leaching. In this study, critical elements (Li, Be, Rb, Sr, Zr, Nb, Cs, Hf, Ta, Ga, Ge, Se, Cd, and Tl) were recovered from CFA of Pingwei power plant in China by alkali fusion-organic acid leaching. The results showed that the leaching rate of critical elements after alkali fusion was higher than that of direct organic acid leaching. The leaching rate of total critical elements was 72.56% under the optimal conditions. Among them, the highest leaching rate of Li, Be and Ga was more than 90%, and the highest leaching rate of Ge, Se, Rb, Sr, Zr, Nb, Cd, Cs and Hf was 70%-90%. Characterization analysis revealed that the amorphous aluminosilicate and silica phases in the raw CFA were destroyed by alkali fusion, resulting in nepheline and soluble aluminosilicate phases which were easily dissolved by citric acid . This study provides theoretical basis and technical support for the extraction of critical elements from CFA.
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
Catalysts
·
2025
·Vol. 15
·期 3
·274
·
IF 4
Xinglei Zhao,Jiamin Ding,Xin Xiao,Chengbo Zhang,Shengyong Lu,Zhanheng Zhu,Sheng Sun
Fly ash produced by Municipal Solid Waste Incineration (MSWI) contains significant quantities of dioxins, posing a major challenge for safe disposal. Compared to other high-temperature disposal methods, low-temperature pyrolysis (<500 °C) can efficiently degrade dioxins in fly ash at relatively low temperatures. To better understand the effects of water-washing and catalysts on dioxin decomposition during low-temperature pyrolysis, this study investigates the impact of water-washing and three different catalysts (V2O5-WO3/TiO2, Fe/C, and CaO) on the decomposition of dioxins in washed fly ash (WFA). The results indicate that, despite the fact that water-washing pretreatment causes dioxin enrichment in WFA, the toxic equivalent quantity (TEQ) of dioxins within WFA remains lower at the identical pyrolysis temperature when contrasted with that in raw fly ash (RFA). Low-temperature pyrolysis carried out at 250 °C is capable of degrading 99.3% of the dioxins present in water-washed fly ash, achieving a significantly better performance compared to the raw fly ash, which has a degradation efficiency of merely 80%. Nevertheless, when the temperature is set at 210 °C, the degradation efficiency of the WFA turns out to be relatively low, only reaching 29%. The addition of catalysts remarkably promoted dioxin degradation at 210 °C. Among them, CaO exhibited the most outstanding performance, achieving a degradation efficiency as high as 94.8%. It should be emphasized that the catalyst ratio plays a pivotal role in the degradation process. Specifically, the proportion of CaO should not to be less than 10 wt.%.
研究领域:
环境科学
·
废物处理
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2024
·Vol. 31
·期 39
·52582-52595
·
IF 0
Zhou Hao,Dang Yan,Chen Xinyu,Ivanets Andrei,Ratko Alexander A.,Kouznetsova Tatyana,Liu Yongqi,Yang Bo,Zhang Xulong,Sun Yiwei,He Xiaoyan,Ren Yanjie,Su Xintai
Due to industrialization, soil heavy metal pollution is a growing concern, with humic substances (HS) playing a pivotal role in soil passivation. To address the long duration of the compost humification problem, coal fly ash (CFA) in situ catalyzes the rapid pyrolysis of the cotton stalk (CS) to produce HS to address Cd passivation. Results indicate that the highest yield of humic acid (HA) (8.42%) and fulvic acid (FA) (1.36%) is obtained when the CS to CFA mass ratio is 1:0.5, at 275 ℃ for 120 min. Further study reveals that CFA catalysis CS humification, through the creation of alkaline pyrolysis conditions, Fe 2 O 3 can stimulate the protein and the decomposition of hemicellulose in CS, and then, through the Maillard and Sugar-amine condensation reaction synthesis HA and FA. Applying HS-CS&CFA in Cd-contaminated soil demonstrates a 26.69% reduction in exchangeable Cd within 30 days by chemical complexation. Excellent maize growth effects and environmental benefits of HS products are the prerequisites for subsequent engineering applications. Similar industrial solid wastes, such as steel slag and red mud, rich in Fe 2 O 3 , can be explored to identify their catalytic humification effect. It could provide a novel and effective way for industrial solid wastes to be recycled for biomass humification and widely applied in remediating Cd-contaminated agricultural soil.
研究领域:
环境科学
·
土壤修复
✓ 已验证
产品关联
DOI
PubMed
WASTE MANAGEMENT
·
2022
·
IF 8.816
Zhikun Zhang,Yanli Wang,Yuqi Zhang,Boxiong Shen,Jiao Ma,Lina Liu
The environmental risk of heavy metals in hazardous municipal solid waste incineration fly ash (FA) is one of the most important concerns for its safely treating and disposing. This study investigated the stabilization behavior of heavy metals in FA using coal fly ash (CFA) as an additive via hydrothermal treatment. The effects of water washing pre-treatment and FA/CFA ratio on leaching behavior, speciation evolution, and risk assessment of heavy metals were studied. The results showed that 96.6–98.0 % of Cl can be effectively removed by water washing pre-treatment and hydrothermal treatment. Most heavy metals (Cr, Cu, Ni, Pb and Zn) (>91.5 %) were stabilized in the hydrothermal product, rather than transferred to liquid phase. Tobermorite can be synthesized by adjusting Ca/Si ratio with the addition of CFA. The heavy metals were transferred into more stable residue fractions with increasing CFA addition, which resulted in the significant reduction of leaching concentrations and risk assessment code (RAC) of heavy metals. Among, the product with 30% CFA exhibited the most superior performance with the lowest leaching concentrations of heavy metals and RAC was at no risk level (<1). In addition, the economic performance of hydrothermal treatment exhibited a potential advantage by comparing with FA-to-cement, FA-to-glass slags and FA-to-chelating agent & cement solidification/stabilization. Therefore, the hydrothermal treatment coupled with water washing pre-treatment would be a promising method for the detoxification of FA, as well as synergistic treatment of FA and CFA.
研究领域:
环境科学
·
废物处理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RESOURCES CONSERVATION AND RECYCLING
·
2023
·
IF 13.2
Li Cui,Lijuan Feng,Hefeng Yuan,Huaigang Cheng,Fangqin Cheng
The recovery of critical metals from industrial waste is very important and challenging. This work proposed an efficient process for recovering aluminum, lithium, iron and gallium from coal fly ash leachate. Firstly, 98.1 %, 86.6 % and 99.8 % of iron, lithium and gallium are coextracted by tributyl phosphate (TBP), facilitating the subsequent use of the aluminum raffinate. The spectroscopic analysis verifies the formation of [Li(TBP) 2 ][FeCl 4 ] and [Li(TBP) 2 ][G a C l 4 ]. Afterwards, the effective separation of lithium, iron, gallium in TBP is achieved by stepwise stripping. Lithium can be almost completely stripped using 6 mol/L HCl with free iron and gallium of loss. An extremely high separation factor of iron and gallium (α Fe/Ga , 1175) can be achieved through reduction stripping by precisely controlling pH value and oxidation–reduction potential. Finally, about 99.5 % of gallium can be stripped with 0 ∼ 1 mol/L HCl. This work realizes the synergistic recovery of valuable metals from waste resources.
研究领域:
环境科学
·
冶金工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）