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
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产品关联
DOI
PubMed
高影响因子
ADVANCED POWDER TECHNOLOGY
·
2025
·
IF 4.2
Jingjing Zou,Yiping Sun,Shuo Liang,Zhongrui Shi,Guanghe Li,Chunbin Guo
This study introduces a novel process for recovering Al 2 O 3 from coal fly ash (CFA), utilizing potassium persulfate (K 2 S 2 O 8 ) as an activator, and explores the decomposition behavior of both crystalline and amorphous alumina phases within CFA. The experiment involved mixing K 2 S 2 O 8 with CFA in K 2 S 2 O 8 /Al 2 O 3 molar ratios ranging from 0.5:1 to 4:1, followed by calcination at varying temperatures and durations to optimize alumina extraction. The results indicated that the alumina extraction efficiency of 91 % was achieved with a molar ratio of 3:1 (K 2 S 2 O 8 /Al 2 O 3 ), calcination temperature of 405 °C, and reaction time of 2 h. X-ray photoelectron spectroscopy, scanning electron microscopy, and reaction kinetics were employed to analyze the reaction mechanism. The findings revealed that K 2 S 2 O 8 preferentially reacted with the amorphous alumina phase, leading to the breakage of Al–O–Si bonds. The release of SO 2 and O 2 during the reaction further facilitated the breakdown of the crystalline phase by disrupting aluminum–oxygen tetrahedra. Simultaneously, the silicon-oxygen tetrahedra decomposes and forms SiO 2 gel layer, wrapping the remaining aluminum oxygen octahedron, thus preventing further alumina extraction. This study contributes to a deeper understanding of the decomposition behavior of crystalline and amorphous alumina phases in CFA during sulfate roasting. The findings provide a theoretical foundation for refining alumina recovery processes and offer significant improvements to existing sulfate roasting methods.
研究领域:
材料科学
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环境科学
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化学工程
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产品关联
DOI
高影响因子
Journal of Central South University
·
2021
·Vol. 28
·期 6
·1652-1664
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IF 1.716
Jiang Chun-lu,Wang Rui,Chen Xing,Zheng Liu-gen,Cheng Hua
Chitosan-coated fly ash (CWF) was prepared by the acid leaching-coating method. Chitosan and fly ash were crosslinked in the solution of acetic acid and sulfuric acid. The microstructure of CWF was conducted by scanning electron microscope (SEM) and X-ray diffraction (XRD). The removal of Cr(VI) from water by CWF was studied by adsorption experiments. The composite prepared by the experiment developed a pore structure and a crystal structure similar to SiO 2 and chitosan chain-like coating was formed on the surface of fly ash. The new modified material has larger surface roughness, specific surface area and more adsorption channels. The Cr(VI) was enriched in modified materials by electrostatic adsorption between CrO 4 2− , CrO 7 2− and —NH 3 + group and surface acid functional groups. The movement of Cr(VI) in solution is a diffusion process from the main body of the liquid phase to the surface of the liquid film.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Jiguang Huang,Haiping Chen,Tian Zhou,Run Qi,Heng Zhang
Coal fly ash (CFA) is a promising substitute material in ceramic membrane fabrication to address the high membrane cost issue. However, supports prepared with CFA usually have wide pore size distributions , leading to difficulties in fabricating separation layers. This study focused on overcoming the selectivity-permeability trade-off of membranes based on the CFA support. Five different sizes of alumina powders were adopted to optimize the particle size for separation layer preparation. The membrane prepared using the powder with mean particle size of 1.11 μm under 1150 °C sintering had the best comprehensive performance. The mean pore size was 161 nm and the permeability was 879.71 L/(m 2 ∙h∙bar). Membranes with smaller coating particles had defects because of the particle penetration while membranes with larger particles showed little pore size difference with the support. This work offers opportunities to broaden the application of low-cost CFA membranes.
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2024
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IF 5.3
Chen Li,Chuncai Zhou,Ye Quan,Shihai Xu,Zixuan Wang,Zhiguo Li,Xin Li,Guijian Liu,Jin Wang
Adsorption of gallium (Ga) utilizing solid waste synthetic materials can achieve both high-value solid waste use and solve the supply–demand paradox of Ga. To efficiently recover Ga in solution, this article describes a hydrothermal synthesis technique of mesoporous materials from the acid leaching residue of coal fly ash (CFA). According to the findings, the mesoporous silica synthesized by hydrothermal reaction with CTAB: nSiO 3 2- =1:0.085 around 120℃ during 24 h exhibits a maximum specific surface area (771.25 m 2 /g) along with hexagonal mesoporous structure. Pseudo-second-order kinetic model that has an excellent correlation coefficient (R 2 > 0.99) can explain this adsorption system. Since Freundlich model fits this adsorption action better, the process is multi-molecular layer adsorption. The thermodynamic fitting results show that the adsorption of Ga by mesoporous silica is an endothermic and spontaneous chaotic reaction. The adsorption mechanism could be depicted using ion exchange and coupling. The adsorption efficiency of Ga is still higher than 80 % after the material has been regenerated by multiple resolution. In conclusion, mesoporous silica prepared by CFA acid leaching residue has the potential to adsorb Ga.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Ruize Gao,Haisen Peng,Qiongqiong He,Zhen Meng,Pengxu Xiang,Lihua Hou,Zhenyong Miao
Lithium (Li), gallium (Ga), and rare earth elements (REEs) are essential in various industries due to their wide range of applications, and extraction of rare metals from coal fly ash (CFA) has become a hot topic in recent years. This study investigates the simultaneous leaching of Li, Ga, and REEs from CFA using both inorganic and organic acids. High leaching efficiencies, exceeding 90%, were achieved for Li (90.4%), Ga (90.5%), and REEs (92.7%) with 3 M HCl leaching. The leaching efficiency of citric acid is lower, but it can achieve a leaching rate of 70–80% at low concentration (0.5 M). A novel two-stage acid leaching approach is proposed for the selective leaching of Li and Ga from CFA. In the first step, 1 M HCl leaching results in the leaching of most Li (71.12%) and a small amount of Ga (2.63%). Subsequently, 2 M HCl leaching led to the leaching of a small amount of Li (18.14%) and most of Ga (83.93%). The silicic acid gel produced during low HCl concentration leaching exhibited a stronger affinity for Ga 3+ than for Li + , with significantly higher adsorption energy for Ga (−211.554 kcal/mol) compared to that for Li (−3.481 kcal/mol). This two-stage acid leaching process ingeniously utilized H 2 SiO 3 to achieve the selective separation and leaching of Li and Ga.
研究领域:
材料科学
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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
SURFACE & COATINGS TECHNOLOGY
·
2025
·
IF 6.1
Weitao Song,Huiping Song,Zhenlian Fan,Shuyan Cheng,Zhengjun Feng
Superhydrophobic coatings have attracted extensive interest from researchers in recent years. An important future development direction involves utilizing zero-cost solid waste materials as structural components to create superhydrophobic coatings. In this article, fly ash(FA), a common solid waste, was used as the main material, epoxy resin (ER) and polydimethylsiloxane (PDMS) were used as the main film-forming substances. A multifunctional FA-superhydrophobic coating ER/FA@PDMS/SiO 2 was prepared by spraying method. FA-superhydrophobic coating exhibited a water contact angle (WCA) of 156.4° ± 0.8° and water sliding angle (WSA) of 4.5° ± 0.1°. ER/FA primer has an irregular porous structure, and the PDMS/SiO 2 penetrate into the porous structure. The porous ER/FA coating can store PDMS and SiO 2 , and the FA superhydrophobic coating has similar rough structure and low surface energy inside and on the surface. FA-superhydrophobic coating have strong mechanical stability, after the surface coating is destroyed, the internal structure of the coating can still maintain excellent performance. The corrosion current density of FA-superhydrophobic coating is about 9.392 × 10 −7 A/cm 2 , which is one order of magnitude lower than ER/FA coating. FA-superhydrophobic coating can delay icing by about 121.55 % under extremely cold conditions. This simple and low-cost superhydrophobic coating has great application value in self-cleaning, anti-icing and anti-corrosion.
研究领域:
材料科学
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表面工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
·
2019
·
IF 1.479
Gang Fu,Juncheng Jiang,Dan Wei,Lei Ni,Zhan Dou,Qiang Chen,Zhen Cheng
The utilization of solid particles in aqueous foam has a great potential in improving fire fighting efficiency. In this study, aqueous foam supported by micro fly-ash (FA) was prepared and its stability in a specific type of oil was characterized. Firstly, different amount of FA was added to study the influence of FA concentration on foamability. It showed that within a specific extent, foam expansion ratio increased with the increasing of FA concentration. And compared with conventional foams, oil resistance of FA stabilized foams, which was investigated by analyzing drainage rate and evolution process with a self-made apparatus, was remarkably improved when FA concentration exceed 4.8wt.%. Secondly, SiO2 and Al2O3 particles with different median sizes were used to study the effect of particle size on stability. However, the smaller hydrophilic particles didn’t behave better as expected. Moreover, the foam stability in three hydrocarbons was evaluated in the same way. The results indicated that the short chain hydrocarbons had much stronger detrimental effect to both two-phase foam and three-phase foam. But overall, the three-phase foam stabilized by FA exhibited much better oil resistance, so it can be used as a promising material for pool fire extinguishing and prevention.GRAPHICAL
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2018
·Vol. 10
·期 5
·523
·
IF 2.935
Limin Zang,Xuan Qiao,Lei Hu,Chao Yang,Qifan Liu,Chun Wei,Jianhui Qiu,Haodao Mo,Ge Song,Jun Yang,Chanjuan Liu
Two magnetic supports with different morphologies and particle sizes were designed and prepared for cellulase immobilization based on chitosan and industrial by-product magnetic coal fly ash (MCFA). One was prepared by coating chitosan onto spherical MCFA particles to form non-porous MCFA@chitosan gel microcomposites (Support I) with a size of several micrometers, and the other was prepared using the suspension method to form porous MCFA/chitosan gel beads (Support II) with a size of several hundred micrometers. Cellulase was covalent binding to the support by glutaraldehyde activation method. The morphology, structure and magnetic property of immobilized cellulase were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and a vibrating-sample magnetometer. The cellulase loading on Support I was 85.8 mg/g with a relatlvely high activity recovery of 76.6%, but the immobilized cellulase exhibited low thermal stability. The cellulase loading on Support II was 76.8 mg/g with a relative low activity recovery of 51.9%, but the immobilized cellulase showed high thermal stability. Cellulase immobilized on Support I had a glucose productivity of 219.8 mg glucose/g CMC and remained 69.9% of the original after 10 cycles; whereas the glucose productivity was 246.4 mg glucose/g CMC and kept 75.5% of its initial value after 10 repeated uses for Support II immobilized cellulase. The results indicate that the two supports can be used as cheap and effective supports to immobilize enzymes.Keywords:magnetic composites;chitosan;coal fly ash;enzyme immobilization
研究领域:
生物工程
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2022
·Vol. 105
·期 9
·5929-5943
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IF 4.186
Jie Ren,Hongfang Sun,Qun Li,Zhenming Li,Xiaogang Zhang,Yanshuai Wang,Linfei Li,Feng Xing
In this research, the effects of natural seawater (SW) on the properties of alkali-activated slag/fly ash (AASF) are studied. AASF prepared with deionized water is set as the reference mixture. The results showed that the use of natural SW resulted in a prolonged setting time and lower heat release, but no obvious impact on the flowability of AASF specimens. The long-term compressive strength became higher when SW was used, whereas the corresponding flexural strength and fractural toughness turned lower. The use of SW induced the formation of new products that were not identified in the reference mixture, such as Cl–hydrocalumite and gypsum. In addition, it is evidenced that the dissolution of fly ash (FA) particles was significantly delayed with the incorporation of SW. All these results were related to the various ions introduced by the natural SW and their interactions with the alkaline activator as well as the precipitation of salts on slag and FA surfaces or in the matrix.
研究领域:
土木工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Cleaner Production
·
2023
·
IF 11.1
Hongxia Fang,Chuncai Zhou,Shihai Xu,Jiaqian Shi,Yunhu Hu,Guijian Liu
A novel method of high-efficiency extraction of aluminum (Al) and lithium (Li) from coal fly ash (CFA) is proposed. The mixture of CFA and sodium pyrosulfate (Na 2 S 2 O 7 ) was subjected to mechanochemical activation, followed by the addition of sodium persulfate (Na 2 S 2 O 8 ) for pressure leaching . The results indicated that the leaching efficiency of Al and Li reached 95.58% and 71.59% for treatment at the molar ratios of Na 2 S 2 O 7 /Al 2 O 3 of 3:1, ball milling of 60 min, molar ratios of Na 2 S 2 O 8 /Al 2 O 3 of 8:1, liquid-solid ratio of 4:1, reaction time of 120 min and temperature of 200 °C, then continued to increase the temperature to 230 °C, 95.45% Li leaching can be further achieved. Leaching residues were studied by multiple solid phase analysis techniques to elucidate the leaching mechanism. It was found that the mechanochemical activation of Na 2 S 2 O 7 effectively broke a portion of Si–O–Al bonds in CFA to form aluminum tri-sodium sulfate, the Na 2 S 2 O 8 was decomposed into hydrogen sulfate (HSO 4 − ) and hydrogen peroxide (H 2 O 2 ) during the pressure leaching, the oxygen released by H 2 O 2 together with water vapor would create a high-pressure environment, allowing HSO 4 − to further disintegrate the Si–O–Al and Si–O bonds, ultimately releasing Al and Li. The extraction kinetics confirmed that the extraction process could be expressed well by the combination of the chemical reaction and interior diffusion, and the apparent activation energies of Al and Li were 28.61 kJ/mol and 26.79 kJ/mol at the temperature range of 140∼200 °C. This finding provides insight into more efficient recovery of Al and Li from CFA.
研究领域:
化学工程
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材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
Crystals
·
2022
·Vol. 12
·期 2
·144
·
IF 2.67
Shun Zhou,Xiaotao Zhang,Han Zhou,Dongxu Li
In the present research work, the ternary effects of varying dosages of graphene oxide encapsulated silica fume (GOSF), nano-silica sol (SS), and fly ash (FA) on the rheological properties, compressive strength, the content and crystal size of calcium hydroxide (CH), porosity, water absorption, and microstructure of cement were studied. The results showed that the incorporation of SF improved the dispersion of GO in the cement matrix. GOSF was prepared through electrostatic attraction between the positively charged SF and negatively charged GO. The ternary mixture of GOSF, SS, and FA had a synergistic effect that improved the performance of cement. When the curing age of cement reached 28 days, the compressive strength reached a peak of 86.5 MPa, the minimum values of content and crystal size of CH were 11.55% and 45.69 nm, respectively, and the minimum values of water absorption and porosity were 0.0011 cm/s0.5and 13.56%, respectively. In terms of microstructure, the denser structure of C-S-H gel and the regular arrangement of CH were noticed.Keywords:silica fume;silica sol;graphene oxide;fly ash;orthogonal experiment
研究领域:
土木工程
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材料科学
✓ 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）