| Citation: |
Xiao-ming Ni, Jing-shuo Zhang, Xiao-kai Xu, Bao-yu Wang, 2024. Molecular structure characterization of middle-high rank coal via 13C NMR, XPS, and FTIR spectroscopy, China Geology, 7, 702-713. doi: 10.31035/cg2022135
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Molecular structure characterization of middle-high rank coal via 13C NMR, XPS, and FTIR spectroscopy
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Abstract
Elemental analysis, nuclear magnetic resonance carbon spectroscopy (13C-NMR), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) experiments were carried out to determine the existence of aromatic structure, heteroatom structure and fat structure in coal. MS (materials studio) software was used to optimize and construct a 3D molecular structure model of coal. A method for establishing a coal molecular structure model was formed, which was “determination of key structures in coal, construction of planar molecular structure model, and optimization of three-dimensional molecular structure model”. The structural differences were compared and analyzed. The results show that with the increase of coal rank, the dehydrogenation of cycloalkanes in coal is continuously enhanced, and the content of heteroatoms in the aromatic ring decreases. The heteroatoms and branch chains in the coal are reduced, and the structure is more orderly and tight. The stability of the structure is determined by the π-π interaction between the aromatic rings in the nonbonding energy EN. Key Stretching Energy The size of EB determines how tight the structure is. The research results provide a method and reference for the study of the molecular structure of medium and high coal ranks.
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References
Chermin HAG, Van Krevelev DW. 1957. Chemical structure and properties of coal. XVII-A mathematical model of coal pyrolysis. Fuel, 36(1), 85–104. GB/T 482-2008 Sampling of coal seams, 2008 (in Chinese). GB/T 482-2008 Method of determining microscopically the reflectance of vitrinite in coal, 2008 (in Chinese). GB/T 6040-2002 General rules for infrared analysis, 2002 (in Chinese). GB/T19500-2004 General rules for X-ray photoelectron spectroscopic analysis method, 2004 (in Chinese). Ge T, Li Y, Wang M, Li F, Zhang MX. 2020. Structural characterization and molecular model construction of gas-fat coal with high sulfur in Shanxi. Spectroscopy and Spectral Analysis, 40(11), 3373–3378. doi: 10.3964/j.issn.1000-0593(2020)11-3373-06. Given PH. 1960. The distribution of hydrogen in coals and its relation to coal structure. Fuel, 39(2), 147. Grzybek T, Pietrazk R, Wachowsk H. 2002. X-ray photoelectron spectroscopy study of oxidized coals coals with different sulphurcontent. Fuel Process Technol, 77, 1–7. Han F, Zhang YG, Meng AH. 2014. FTIR analysis of Yunnan Lignit. Journal of China Coal Society, 39(11), 2293–2299 (in Chinese with English abstract). Hao PY, Meng YJ, Zeng FG, Yan TT, Xu GB. 2020. Quantitative study of chemical structures of different rank coals based on infrared spectroscopy. Spectroscopy and spectral analysis, 40(3), 787–792. doi: 10.3964/j.issn.1000-0593(2020)03-0787- 06. doi: 10.3964/j.issn.1000-0593(2020)03-0787-06. Jawad AH, Ismail K, Ishak MAM, Wilson LD. 2019. Conversion of malaysian low-rank coal to mesoporous activated carbon: Structure characterization and adsorption properties. Chinese Journal of Chemical Engineering, 27(7), 1716–1727. doi: 10.1016/j.cjche.2018.12.006. Jiang JY, Yang WH, Cheng YP, Liu ZD, Zhang Q, Zhao K. 2019. Molecular structure characterization of middle-high rank coal via XRD, Raman and FTIR spectroscopy: Implications for coalification. Fuel, 239, 559–572. doi: 10.1016/j.fuel.2018.11.057. Kozlowski M. 2004. XPS study of reductively and non-reductively modified coals. Fuel, 83(3), 259–265. doi: 10.1016/j.fuel.2003.08.004. Li X, Zeng FG, Wang W, Dong K, Cheng LY, 2015. FTIR characterization of structural evolution in low-midlle rank coals. Journal of China Coal Society, 40(12), 2900‒2908. doi: 10.13225lj.cnki.jccs.2015.1085. Li W, Zhu YM, Wang G, Jiang B. 2016. Characterization of coalifica-tion jumps during high rank coal chemical structure evolution. Fuel, 185, 298–304. doi: 10.1016/j.fuel.2016.07.121. Liu Y, Zhu YM, Li W, Zhang CH, Wang Y. 2017. Ultra micropores in macromolecular structure of subbituminous coal vitrinite. Fuel, 210, 298–306. doi: 10.1016/j.fuel.2017.08.069. Liu WY, Liu QF, Liu LS, Liu D. 2019. Study on FTIR features of middle and high rank coal structure in north part of Qinshui Basin. Journal of Coal Science and Technology, 47(2), 181–187. doi: 10.13199/j.carolcarrollnkiCST.2019.02.030. Liu BJ, Chu GC, Zhao CL, Sun YZ. 2022. Leaching behavior of Li and Ga from granitic rocks and sorption on kaolinite: Implications for their enrichment in the Jungar Coalfield, Ordos Basin. China Geology, 5(1), 34–45. doi: 10.31035/cg2021024. Marzec A. 2000. Intermolecular interactions of aromatic hydrocarbons in carbonaceous materials a molecular and quantum mechanics. Carbon, 38(3), 1863–1871. Metrological Specifications of the People’s Republic of China. 2011. JJF1321-2011 Calibration Specification for Elemental Analyzers. Ping A, Xia W, Peng Y, Xie GY, 2020. Construction of bituminous coal vitrinite and inertinite molecular assisted by 13C NMR, FTIR and XPS. Journal of Molecular Structure, 1222, 128959. doi: 10.1016/j.molstruc.2020.128959. Shinne JH. 1984. From coal to single stage and two-stage products: A reactive model of coal structure. Fuel, 63(9), 1187–1196. doi: 10.1016/0016-2361(84)90422-8. Song Y, Zhu YM, Li W, 2017. Macromolecule simulation and CH4 adsorption mechanism of coal vitrinite. Applied Surface Science, 396, 291‒302. doi: 10.1016/j.apsusc.2016.10.127. Surip SN, Ahmed Saud A, Zaharaddeen NG, Syed SA, Syed-Hassan KI, Ali HJ. 2020. H2SO4-treated malaysian low rank coal for methylene blue dye decolourization and COD reduction: Optimization of adsorption and mechanism study. Surfaces and Interfaces, 21, 100641. doi: 10.1016/j.surfin.2020.100641. Jia TG, Li X, Qu GN, Li W, Yao HF, Liu TF. 2021. FTIR characterization of chemical structures characteristics of coal samples with different metamorphic degrees. Spectroscopy and Spectral Analysis, 41(11), 3363–3369. doi: 10.3964/j.issn.1000-0593(2021)11-3363-07. Wiser WH. 1975. Reported in division of fuel chemistry. Preprints, 20(1), 122. Xiang JH, Zeng FG, Liang HZ, Ll MF, SONG XX, ZHAO YY. 2016. Carbon structurecharacteristics and evolution mechanism of coal with different metamorphic degrees. Journal of China Coal Society, 41(6), 1498–1506 (in Chinese with English abstract). Xie HP, Wang JH, Wang GF, Ren HW, Liu JZ, Ge SR, Zhou HW, Wu G, Ren SH. 2018. The new concept of coal revolution and the conception of coal science and technology development. Journal of China Coal Society, 43(5), 1187–1197 (in Chinese with English abstract). Yan JH, Lei ZP, Li ZK, Wang ZC, Ren SB, Kang SG, Wang XL, Shui HF, 2020. Molecular structure characterization of low-medium rank coals via XRD, solid state 13C NMR and FTIR spectroscopy. Fuel, 268, 117038. doi: 10.1016/j.fuel.2020.117038. Zhao YG, Li MF, Zeng FG. 2018. FTIR study of structural characteristics of different chemical components from Yimin Lignite. Journal of China Coal Society, 43(2), 546–554 (in Chinese with English abstract). Zhou XY, Zeng FG, Xiang JH, Deng XP, Xiang XH. 2020. Macromolecular model construction and molecular simulation of organic matter in Majiliang vitrain. CIESC Journal, 71(4), 1802–1811 (in Chinese with English abstract). -
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Xiao-ming Ni, Jing-shuo Zhang, Xiao-kai Xu, Bao-yu Wang, 2024. Molecular structure characterization of middle-high rank coal via 13C NMR, XPS, and FTIR spectroscopy, China Geology, 7, 702-713. doi: 10.31035/cg2022135
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Figure 1.
Peak fitting 13C CP/MAS spectra. a‒PDS Coal; b‒HB Coal; c-XG Coal; d-CP Coal; e-SH Coal; f-Compares the overall spectra of the five coal samples.
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Figure 2.
Peak fitting FTIR spectra of PDS. a‒Peak fitting of aromatic hydrocarbons spectra; b‒peak fitting of oxygen-containing functional groups; c‒peak fitting of aliphatic hydrocarbons spectra; d‒peak fitting of hydroxyl hydrogen bond spectra.
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Figure 3.
Chemical structure changes of aromatic hydrocarbons.
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Figure 4.
Chemical structure changes of aliphatic hydrocarbons.
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Figure 5.
Peak fitting binding energy spectra of PDS. a‒peak fitting of S spectra; b‒peak fitting of C spectra; c‒peak fitting of N spectra; d‒peak fitting of O spectra.
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Figure 6.
Planar model and spectra comparison.
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Figure 7.
Comparison diagram of molecular structure model optimization. In the ball-and-stick model, the gray is carbon atoms; the white sphere is hydrogen; the red ball is oxygen; the blue balls are nitrogen atoms.
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Figure 8.
Surface area analysis diagram.