Effect of oxygen-containing functional groups on the wettability of coal through DFT and MD simulation
To investigate the wettability of different oxygen-containing functional group (OFG) surfaces, graphite substrates were used as a model for coal adsorbents. The substrates were modified with COOH, OH, CO, and OCH3. The adsorption-diffusion behavior of H2O molecules/water droplets on different O...
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Elsevier
2023-04-01
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| Series: | Arabian Journal of Chemistry |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1878535223000679 |
| _version_ | 1811159943407992832 |
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| author | Dan Zhao Xiaoqing Liu Zhiyuan Shen |
| author_facet | Dan Zhao Xiaoqing Liu Zhiyuan Shen |
| author_sort | Dan Zhao |
| collection | DOAJ |
| description | To investigate the wettability of different oxygen-containing functional group (OFG) surfaces, graphite substrates were used as a model for coal adsorbents. The substrates were modified with COOH, OH, CO, and OCH3. The adsorption-diffusion behavior of H2O molecules/water droplets on different OFG surfaces was investigated using molecular dynamics (MD) simulations with frontier orbital energy difference as a metric for different surface wettability degrees in quantum chemical analysis. The results indicated that the frontier orbital energy difference of the H2O molecule was 3.480, 3.491, 3.631, and 3.680 eV for PhCOOH, PhOH, PhCO, and PhOCH3, respectively. In addition, the equilibrium contact angle, interaction energy, and number of hydrogen bonds after the adsorption equilibrium of water droplets for COOH, OH, CO, and OCH3 surfaces were 22.34°, −5.03 kcal/mol, and 652; –23.72°, −4.19 kcal/mol, and 450; 68.01°, −0.79 kcal/ mol, and 61; 90.51°, −0.50 kcal/mol, and 28, respectively. The smaller the energy difference between the frontier orbitals of the H2O molecule and the OFG, the smaller the equilibrium contact angle between the water droplet and the OFG surface, the more hydrogen bonds were formed, and the larger the absolute value of the interaction energy, the better the wettability of the surface of the OFG. The order of wettability of the different OFG surfaces was COOH > OH > CO > OCH3, which is consistent with the radial distribution function and the analysis results for the extended area, etc. The results of density functional theory (DFT) calculations and MD simulations exhibited identical patterns, indicating the reasonableness of the simulations. This study may serve as a reference for the suppression of hydrophilicity in low-order coal and the enhancement of the flotation effect. |
| first_indexed | 2024-04-10T05:49:16Z |
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| language | English |
| last_indexed | 2024-04-10T05:49:16Z |
| publishDate | 2023-04-01 |
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| series | Arabian Journal of Chemistry |
| spelling | doaj.art-06a2cb6120924325ae8feeb54fc4de862023-03-05T04:24:00ZengElsevierArabian Journal of Chemistry1878-53522023-04-01164104606Effect of oxygen-containing functional groups on the wettability of coal through DFT and MD simulationDan Zhao0Xiaoqing Liu1Zhiyuan Shen2College of Safety Science & Engineering, Liaoning Technical University, Fuxin 123000, China; Key Laboratory of Mine Thermo-motive Disaster and Prevention, Ministry of Education, Liaoning Technical University, Huludao 125105, ChinaCollege of Safety Science & Engineering, Liaoning Technical University, Fuxin 123000, China; Key Laboratory of Mine Thermo-motive Disaster and Prevention, Ministry of Education, Liaoning Technical University, Huludao 125105, China; Corresponding author at: College of Safety Science & Engineering, Liaoning Technical University, Fuxin 123000, China.College of Safety Science & Engineering, Liaoning Technical University, Fuxin 123000, China; Key Laboratory of Mine Thermo-motive Disaster and Prevention, Ministry of Education, Liaoning Technical University, Huludao 125105, ChinaTo investigate the wettability of different oxygen-containing functional group (OFG) surfaces, graphite substrates were used as a model for coal adsorbents. The substrates were modified with COOH, OH, CO, and OCH3. The adsorption-diffusion behavior of H2O molecules/water droplets on different OFG surfaces was investigated using molecular dynamics (MD) simulations with frontier orbital energy difference as a metric for different surface wettability degrees in quantum chemical analysis. The results indicated that the frontier orbital energy difference of the H2O molecule was 3.480, 3.491, 3.631, and 3.680 eV for PhCOOH, PhOH, PhCO, and PhOCH3, respectively. In addition, the equilibrium contact angle, interaction energy, and number of hydrogen bonds after the adsorption equilibrium of water droplets for COOH, OH, CO, and OCH3 surfaces were 22.34°, −5.03 kcal/mol, and 652; –23.72°, −4.19 kcal/mol, and 450; 68.01°, −0.79 kcal/ mol, and 61; 90.51°, −0.50 kcal/mol, and 28, respectively. The smaller the energy difference between the frontier orbitals of the H2O molecule and the OFG, the smaller the equilibrium contact angle between the water droplet and the OFG surface, the more hydrogen bonds were formed, and the larger the absolute value of the interaction energy, the better the wettability of the surface of the OFG. The order of wettability of the different OFG surfaces was COOH > OH > CO > OCH3, which is consistent with the radial distribution function and the analysis results for the extended area, etc. The results of density functional theory (DFT) calculations and MD simulations exhibited identical patterns, indicating the reasonableness of the simulations. This study may serve as a reference for the suppression of hydrophilicity in low-order coal and the enhancement of the flotation effect.http://www.sciencedirect.com/science/article/pii/S1878535223000679Oxygen-containing functional groupsElectrostatic potentialFrontier orbitalEquilibrium contact angleNumber of hydrogen bonds |
| spellingShingle | Dan Zhao Xiaoqing Liu Zhiyuan Shen Effect of oxygen-containing functional groups on the wettability of coal through DFT and MD simulation Arabian Journal of Chemistry Oxygen-containing functional groups Electrostatic potential Frontier orbital Equilibrium contact angle Number of hydrogen bonds |
| title | Effect of oxygen-containing functional groups on the wettability of coal through DFT and MD simulation |
| title_full | Effect of oxygen-containing functional groups on the wettability of coal through DFT and MD simulation |
| title_fullStr | Effect of oxygen-containing functional groups on the wettability of coal through DFT and MD simulation |
| title_full_unstemmed | Effect of oxygen-containing functional groups on the wettability of coal through DFT and MD simulation |
| title_short | Effect of oxygen-containing functional groups on the wettability of coal through DFT and MD simulation |
| title_sort | effect of oxygen containing functional groups on the wettability of coal through dft and md simulation |
| topic | Oxygen-containing functional groups Electrostatic potential Frontier orbital Equilibrium contact angle Number of hydrogen bonds |
| url | http://www.sciencedirect.com/science/article/pii/S1878535223000679 |
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