FUEL
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2024
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IF 6.7
Zili Yang,Yangchao Xia,Yanzhen Fu,Qinshan Liu,Ming Li,Xiahui Gui
Effective inhibition of clay minerals remains a challenge in the flotation separation of fine coal with high ash content. The quest for efficient, environmentally friendly, and cost-effective depressants to improve the flotation efficiency of fine coal-slime has become a focus of current research. Humic acid (HA), a macromolecular organic compound widely present in nature, is known for its non-toxic, low-cost, and biodegradable properties. In this study, the potential selective depressant HA was utilized to enhance the recovery of low-ash clean coal in the coal-kaolinite system. Adsorption and inhibition mechanisms were explored through contact angle measurements, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) methods. Flotation tests demonstrated that HA, at varying dosages, significantly increased combustible matter recovery while reducing ash recovery compared to conventional flotation. Optimal conditions, with an HA dosage of 750 g/t, resulted in a combustible matter recovery of 40.56 % and an ash content of 17.77 % in the clean coal. Contact angle measurements confirmed that high-dosage HA significantly reduces the coal surface hydrophobicity, resulting in a rapid decline in the recovery of combustible matter. It did not significantly alter the contact angle of kaolinite, however, across the entire range of HA dosages. Furthermore, XPS studies revealed that the reduction in hydrophobicity on the coal surface after HA adsorption is mainly attributed to the coverage of surface carbon–carbon/carbon-hydrogen groups (C–C/C–H) and the increased presence of carbonyl groups (C = O). Additionally, the study found that HA predominantly adsorbs on the Si-OH groups of kaolinite. Finally, AFM results showed that the primary mechanism underlying the altered heterocoagulation behavior between coal and kaolinite is HA’s effect on their interaction forces. The optimal flotation results achieved at the HA dosage of 750 g/t are primarily attributed to the consistent presence of repulsive forces during the approach process and weak adhesion forces during the retraction process between coal and kaolinite, thus reducing kaolinite coating on the coal surface. These findings provide a promising direction for utilizing HA to enhance flotation deashing of high-ash coal-slime.
研究领域:
矿物加工工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Coal Preparation and Utilization
·
2025
·
IF 2.1
Jinwei Diao,Peng Chen,Yong Huang,Xiaoqian Zhang,Ningbo Wang,Yanan Gao,Shaoxian Song,Jianbo Li
China heavily relies on foreign oil due to limited domestic resources. Oil shortages can be effectively alleviated through Indirect Coal Liquefaction (ICL), though its conversion efficiency is constrained by the coal’s ash content. Therefore, deep de-ashing of raw coal is vital for coal pyrolysis gasification. In this study, the methods for preparing high-purity coal and its impact on coal-to-oil conversion were investigated. When the stirring speed of the hydrophobic agglomerates reached 1800 r/min, the dosage of kerosene was 3 kg/t, and the dosage of methyl isobutyl carbinol (MIBC) and starch was increased to 300 g/t, high-purity coal with an ash content of 1.87% was successfully produced. The gangue mineral (including calcite, quartz and pyrite) removal was 69%. Compared to coal before de-ashing (with an ash content of 6.22%), the carbon conversion rate of high-purity coal in the pyrolysis gasification process increased by 2.28%, the relative CO content increased by 4.49%, and the relative CO2 content decreased by 3.69%, achieving a reduction in CO2 emissions. This is great significance in realizing the double control of carbon emission intensity and total emission.
研究领域:
煤化学
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能源化工
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洁净煤技术
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化学工程
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燃料加工
✓ 已验证
产品关联
DOI
高影响因子
PROCESS BIOCHEMISTRY
·
2024
·
IF 3.7
Xuyang Chen,Hao Liu,Chao Lei,Yirui Lin,Bi Shi,Yunhang Zeng
Bating animal hides with trypsin is an essential step for making leathers. But the mechanism why the calcium in the hide influences the bating performance remains unclear. Here, the enzyme activity of trypsin was determined using N-alpha-benzoyl-L-arginine ethyl ester, bovine albumin (BSA) and collagen fibres as substrates in the presence and absence of calcium salts. The interactions of calcium with trypsin, BSA and collagen were analysed by fluorescence spectroscopy and molecular docking. Data reveal that calcium which binds to BSA and collagen improves the structural stability and enzyme resistance of hide proteins. As a result, a high calcium content of delimed hide is useful to obtain an intact surface of bated hide. However, a low calcium content of hide for pickling is necessary for producing leathers with high physical properties and uniform colour. According to these results, a novel bating system involving deliming, bating and redeliming operations was developed. This system provides a high calcium content of hide for bating and a low calcium content of hide for subsequent pickling and tanning, which effectively reduces the risk of hide damage and improves the physical properties and colour uniformity of leather.
研究领域:
化学
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生物化学
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材料科学
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皮革技术
✓ 已验证
产品关联
DOI
高影响因子
Journal of Cleaner Production
·
2021
·
IF 9.297
Yafei Zhang,Hui Liu,Keyong Tang,Jie Liu,Xiumin Li
Large amounts of water and leather chemicals such as sodium sulfide and calcium hydroxide are used in conventional leather production, resulting in huge amount of wastewater and serious environmental pollution . Enzyme is eco-benign, and an ideal alternative to conventional chemicals attributed to its excellent characteristics and high efficiency. In this work, enzymes with different ions are used in beamhouse to remove the interfibrillar substance and open collagen fiber bundles. Analysis of the opened collagen fibers shows that the enzyme with both hydrogen phosphate and magnesium ions have the best effect in opening collagen fiber bundles. Results of wastewater analysis and the staining of hematoxylin-eosin (H&E) and Verhoeff’s Van Gieson (EVG) indicated the excellent removal of interfibrillar substance by all ion-assisted trials, suggesting an improved removal efficiency. The mechanical properties and shrinkage temperature of the leathers are similar to those of the conventional leathers. Since both deliming and bating are no longer required, a large amount of water can be saved, the leather making time can be shortened, and the cost of wastewater treatment can be reduced. Ion-assisted enzyme method is more efficient and environmentally friendly than the conventional one with sodium sulfide. This work presents a promising path for the cleaner leather making.
研究领域:
化学
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环境科学
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材料科学
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生物技术
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2023
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IF 9.8
Shipeng Sun,Qing Wang,Xinmin Wang,Chunlei Wu,Xu Zhang,Jingru Bai,Baizhong Sun
Agroforestry Waste (AW) is seen as a carbon neutral resource. However, the poor quality of AW reduced its potential application value. Even more unfortunately, chlorine in AW led to the formation of organic pollutants such as dioxins under higher temperatures. Alkali and alkaline earth metals (AAEMs) in ash may deepen the reaction degree. Co-pretreatment of dry torrefaction and de-ashing followed by thermochemical conversion is a promising technology, which can improve raw material quality, inhibit the release of organic pollutants and transform AW into eco-friendly energy carriers. In order to better understand the process, theoretical basis such as the structural characteristics, thermal properties and separation methods of structural components of AW are described in detail. In addition, dry torrefaction related reactors, process parameters, kinetic analysis models as well as the evaluation methods of torrefaction degree and environmental impact are systematically reviewed. The problem of ash accumulation caused by dry torrefaction can be well solved by de-ashing pretreatment . This paper provides a comprehensive discussion on the role of the two- and three-stage conversion technologies around dry torrefacion, de-ashing pretreatment and thermochemical conversion in products quality enhancement. Finally, the existing technical challenges, including suppression of gaseous pollutant release, harmless treatment and reuse of torrefaction liquid product (TPL) and reduction of torrefaction operating costs, are summarized and evaluated. The future research directions, such as vitrification of the reused TPL (after de-ashing or acid catalysis) and integration of oxidative torrefaction with thermochemical conversion technologies, are proposed.
研究领域:
可再生能源
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废物管理
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环境工程
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化学工程
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生物能源
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）