scholarly journals Study on Chemical Bond Dissociation and the Removal of Oxygen-Containing Functional Groups of Low-Rank Coal during Hydrothermal Carbonization: DFT Calculations

ACS Omega ◽  
2021 ◽  
Vol 6 (39) ◽  
pp. 25772-25781
Author(s):  
Han Dang ◽  
Guangwei Wang ◽  
Chunmei Yu ◽  
Xiaojun Ning ◽  
Jianliang Zhang ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Chemical Bond ◽  
Functional Groups ◽  
Hydrothermal Carbonization ◽  
Low Rank ◽  
Low Rank Coal ◽  
Bond Dissociation

Study on Low-Temperature Oxidation Process of Low Rank Coal by In Situ FTIR

2013 ◽  
Vol 652-654 ◽  
pp. 871-876 ◽  
Author(s):  
Xiao Xing Zhong ◽  
Guo Lan Dou ◽  
Hai Hui Xin ◽  
De Ming Wang
Keyword(s):  
Low Temperature ◽  
Functional Groups ◽  
Oxidation Process ◽  
Low Rank ◽  
In Situ Ftir ◽  
Low Rank Coal ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Low Temperature Process

Low temperature oxidation of two different low rank coals was measured by in-situ FTIR. Curve-fitting analysis was employed to identify functional groups types of raw coals, and series technology was carried out on in-situ infrared spectrum of sample coals at low-temperature oxidation process to analyze the changes of main active functional groups with temperature. The results indicate that -CH3, -CH2, -OH, C=O, COOH are the main active functional groups in low rank coal. In the oxidation process, with temperature increasing, the methyl and methylene show the tendency of increase after decrease and then decrease, and all of hydroxyl, carboxyl and carbonyl group present the tendency of increase after decrease, there exists some differences among the main functional groups in the coal low-temperature process.

Comparative Study on Microwave Co-Pyrolysis Products of Low Rank Coal in CO2 and N2 Atmosphere

2014 ◽  
Vol 1033-1034 ◽  
pp. 142-145
Author(s):  
Jun Zhou ◽  
Zhe Yang ◽  
Wen Zhi Shang ◽  
Qiu Li Zhang ◽  
Yong Hui Song ◽  
...  
Keyword(s):  
Comparative Study ◽  
Functional Groups ◽  
Low Rank ◽  
Gas Chromatography Mass Spectrometry ◽  
Lower Content ◽  
Low Rank Coal ◽  
Fixed Carbon ◽  
Pyrolysis Products ◽  
Liquid Products ◽  
New Research

Microwave pyrolysis of coal is a new research method for deeply processing of low rank coal. This paper conducted comparative study on microwave co-pyrolysis products of low rank coal in CO2 and N2 atmosphere. The composition and content of tar and bluecoke were analyzed by gas chromatography-mass spectrometry and FTIR spectroscopy. The results showed that the yields of liquid products in CO2 and N2 atmosphere were 20.6% and 18.0% respectively, and the yields of bluecoke were 62.0% and 65.8%. Bluecoke obtained from CO2 pyrolysis atmosphere had the lower content of fixed carbon and oxygenic functional groups, but the higher content of volatile. There was the lower content of aromatic hydrocarbons and the higher content of oxygenic functional groups in the tar produced in CO2 pyrolysis atmosphere due to CO2 gasification effect.

INVESTIGATING A LINK BETWEEN LOW-RANK COAL BEARING CARRIZO-WILCOX AQUIFER WATER AND KIDNEY DISEASE IN EAST TEXAS

2018 ◽  
Author(s):  
Jayeeta Chakraborty ◽  
◽  
Robert B. Finkelman ◽  
William H. Orem ◽  
Matthew S. Varonka ◽  
...  
Keyword(s):  
Kidney Disease ◽  
Low Rank ◽  
East Texas ◽  
Low Rank Coal

scholarly journals Development and Characterization of Composite Carbon Adsorbents with Photocatalytic Regeneration Ability: Application to Diclofenac Removal from Water

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 173
Author(s):  
Velma Beri Kimbi Yaah ◽  
Satu Ojala ◽  
Hamza Khallok ◽  
Tiina Laitinen ◽  
Marcin Selent ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Functional Groups ◽  
Specific Surface Area ◽  
Palm Kernel ◽  
Hydrothermal Carbonization ◽  
Carbon Composite ◽  
Carbon Adsorbents ◽  
Regeneration Ability ◽  
Activation Temperature

This paper presents results related to the development of a carbon composite intended for water purification. The aim was to develop an adsorbent that could be regenerated using light leading to complete degradation of pollutants and avoiding the secondary pollution caused by regeneration. The composites were prepared by hydrothermal carbonization of palm kernel shells, TiO2, and W followed by activation at 400 °C under N2 flow. To evaluate the regeneration using light, photocatalytic experiments were carried out under UV-A, UV-B, and visible lights. The materials were thoroughly characterized, and their performance was evaluated for diclofenac removal. A maximum of 74% removal was observed with the composite containing TiO2, carbon, and W (HCP25W) under UV-B irradiation and non-adjusted pH (~5). Almost similar results were observed for the material that did not contain tungsten. The best results using visible light were achieved with HCP25W providing 24% removal of diclofenac, demonstrating the effect of W in the composite. Both the composites had significant amounts of oxygen-containing functional groups. The specific surface area of HCP25W was about 3 m2g−1, while for HCP25, it was 160 m2g−1. Increasing the specific surface area using a higher activation temperature (600 °C) adversely affected diclofenac removal due to the loss of the surface functional groups. Regeneration of the composite under UV-B light led to a complete recovery of the adsorption capacity. These results show that TiO2- and W-containing carbon composites are interesting materials for water treatment and they could be regenerated using photocatalysis.

scholarly journals Surface Chemical Heterogeneity of Low Rank Coal Characterized by Micro-FTIR and Its Correlation with Hydrophobicity

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 239
Author(s):  
Wei Wang ◽  
Long Liang ◽  
Yaoli Peng ◽  
Maria Holuszko
Keyword(s):  
Surface Chemistry ◽  
Functional Group ◽  
Group Composition ◽  
Contact Angles ◽  
Low Rank ◽  
Surface Chemical ◽  
Carbonyl Groups ◽  
Low Rank Coal ◽  
Different Types ◽  
Aliphatic Carbon

Micro-Fourier transform infrared (micro-FTIR) spectroscopy was used to correlate the surface chemistry of low rank coal with hydrophobicity. Six square areas without mineral impurities on low rank coal surfaces were selected as testing areas. A specially-designed methodology was applied to conduct micro-FTIR measurements and contact angle tests on the same testing area. A series of semi-quantitative functional group ratios derived from micro-FTIR spectra were correlated with contact angles, and the determination coefficients of linear regression were calculated and compared in order to identify the structure of the functional group ratios. Finally, two semi-quantitative ratios composed of aliphatic carbon hydrogen, aromatic carbon hydrogen and two different types of carbonyl groups were proposed as indicators of low rank coal hydrophobicity. This work provided a rapid way to predict low rank coal hydrophobicity through its functional group composition and helped us understand the hydrophobicity heterogeneity of low rank coal from the perspective of its surface chemistry.

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