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Zhou Y, Huang M, Tian F, Shi X, Zhang X. Einstein-Stokes relation for small bubbles at the nanoscale. J Chem Phys 2024; 160:054109. [PMID: 38341701 DOI: 10.1063/5.0189490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 01/15/2024] [Indexed: 02/13/2024] Open
Abstract
As the physicochemical properties of ultrafine bubble systems are governed by their size, it is crucial to determine the size and distribution of such bubble systems. At present, the size or size distribution of nanometer-sized bubbles in suspension is often measured by either dynamic light scattering or the nanoparticle tracking analysis. Both techniques determine the bubble size via the Einstein-Stokes equation based on the theory of the Brownian motion. However, it is not yet clear to which extent the Einstein-Stokes equation is applicable for such ultrafine bubbles. In this work, using atomic molecular dynamics simulation, we evaluate the applicability of the Einstein-Stokes equation for gas nanobubbles with a diameter less than 10 nm, and for a comparative analysis, both vacuum nanobubbles and copper nanoparticles are also considered. The simulation results demonstrate that the diffusion coefficient for rigid nanoparticles in water is found to be highly consistent with the Einstein-Stokes equation, with slight deviation only found for nanoparticle with a radius less than 1 nm. For nanobubbles, including both methane and vacuum nanobubbles, however, large deviation from the Einstein-Stokes equation is found for the bubble radius larger than 3 nm. The deviation is attributed to the deformability of large nanobubbles that leads to a cushioning effect for collision-induced bubble diffusion.
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Affiliation(s)
- Youbin Zhou
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
| | - Mengyuan Huang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
- Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden 01328, Germany
| | - Falin Tian
- Laboratory of Theoretical and Computational Nanoscience, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Xinghua Shi
- Laboratory of Theoretical and Computational Nanoscience, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Xianren Zhang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
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Liu C, Zhang Y, Yang L, Wang C, Lu X, Lin S. Molecular dynamics of the spontaneous generation mechanism of natural gas hydrates during methane nanobubble rupture. Phys Chem Chem Phys 2023; 25:22862-22869. [PMID: 37587860 DOI: 10.1039/d3cp02823b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2023]
Abstract
Natural gas hydrates have garnered significant attention as a potential new source of alternative energy, and understanding their formation mechanism is of paramount importance for efficient utilization and pipeline transportation. However, there is no consensus among academics on the formation mechanism of natural gas hydrates. In this paper, we propose a method for promoting the rapid formation of natural gas hydrates based on the rupture of methane nanobubbles, which creates local high temperature and pressure to facilitate the mixing of methane and water. The rapid decrease in system temperature and pressure during the process further enhances the formation of gas hydrates. Using molecular dynamics simulations, we theoretically verify the formation of natural gas hydrates. Our results indicate that the instantaneous rupture of methane nanobubbles induced by shock waves leads to a dramatic increase in the local molecular motion velocity around the bubbles. This results in extreme local high temperature and high pressure, leading to complete mixing of methane and water and rapid formation of gas hydrates during the cooling and pressure drop of the mixture. We confirm our findings by analyzing F3-order parameters, F4-order parameters, and water cage statistics.
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Affiliation(s)
- Changsheng Liu
- State Key Laboratory of Marine Resource Utilization in South China Sea, School of Materials Science and Engineering, Hainan University, Haikou 570228, China.
| | - Yan Zhang
- State Key Laboratory of Marine Resource Utilization in South China Sea, School of Materials Science and Engineering, Hainan University, Haikou 570228, China.
| | - Liang Yang
- State Key Laboratory of Marine Resource Utilization in South China Sea, School of Materials Science and Engineering, Hainan University, Haikou 570228, China.
| | - Caizhuang Wang
- Ames Laboratory and Department of Physics, Iowa State University, Ames, IA 50011, USA
| | - Xihong Lu
- MOE of the Key Laboratory of Bioinorganic and Synthetic Chemistry, The Key Lab of Low-carbon Chem & Energy Conservation of Guangdong Province, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China.
| | - Shiwei Lin
- State Key Laboratory of Marine Resource Utilization in South China Sea, School of Materials Science and Engineering, Hainan University, Haikou 570228, China.
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Zheng X, Cheng L, Liu B, Ban S, Chen G. A molecular dynamic simulation on the memory effect of methane hydrate. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Influence of pipeline steel surface on the thermal stability of methane hydrate. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Molecular Insights into Factors Affecting the Generation Behaviors, Dynamic Properties, and Interfacial Structures of Methane Gas Bubbles. WATER 2022. [DOI: 10.3390/w14152327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Molecular dynamics simulations were performed to study the effects of temperatures, pressures, and methane mole fractions on the generation behaviors, dynamic properties, and interfacial structures of methane gas bubbles. Methane gas bubbling can be promoted by high temperatures and high mole fractions of methane, which come from the generation of larger methane clusters in solution. Bubbles were found to be highly dynamic, with more methane molecules exchanging between bubbles and the surrounding solution at high pressures and in systems with high mole fractions of methane. The interfacial structures between bubbles and the surrounding solution were rough at a molecular level, and the roughness of the outermost methane and water molecules was high at high temperatures, low pressures, and in systems with high methane mole fractions. The dissolution of methane molecules depended on the interactions between the outermost methane and water molecules, which would become stronger with decreasing temperatures, increasing pressures, and decreasing methane mole fractions. The results obtained can help in understanding both the generation behaviors of bubbles when gas hydrates decompose and the re-nucleation behaviors of gas hydrates in the presence of bubbles.
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Zhou W, Jiang L, Liu X, Hu Y, Yan Y. Molecular insights into the effect of anionic-nonionic and cationic surfactant mixtures on interfacial properties of oil-water interface. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.128259] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Zhao J, Jin J, Lv K, Sun J, Wang R, Wang J, Guo X, Hou Q, Liu J, Bai Y, Huang X, Liu J. Effects of PVP and NaCl on the decomposition of methane hydrate by MD simulation. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2021.127817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Guo Q, Hu W, Zhang Y, Zhang K, Dong B, Qin Y, Li W. Molecular dynamics simulation of the interfacial properties of methane-water and methane-brine systems. MOLECULAR SIMULATION 2021. [DOI: 10.1080/08927022.2021.1929969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Qiuyi Guo
- Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian, People’s Republic of China
| | - Wenfeng Hu
- Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian, People’s Republic of China
| | - Yue Zhang
- Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian, People’s Republic of China
| | - Kun Zhang
- School of Ocean and Civil Engineering, Dalian Ocean University, Dalian, People’s Republic of China
| | - Bo Dong
- Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian, People’s Republic of China
- School of Energy and Power Engineering, Dalian University of Technology, Dalian, People’s Republic of China
| | - Yan Qin
- Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian, People’s Republic of China
- School of Energy and Power Engineering, Dalian University of Technology, Dalian, People’s Republic of China
| | - Weizhong Li
- Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian, People’s Republic of China
- School of Energy and Power Engineering, Dalian University of Technology, Dalian, People’s Republic of China
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