{"title":"Molecular Insights into the Microscopic Behavior of CO2 Hydrates in Oceanic Sediments: Implications for Carbon Sequestration","authors":"Fengyi Mi, Wei Li, Jiangtao Pang, Othonas A. Moultos, Fulong Ning, Thijs J.H. Vlugt","doi":"10.1021/acs.jpcc.4c05413","DOIUrl":null,"url":null,"abstract":"Knowledge of the microscopic behavior of CO<sub>2</sub> hydrates in oceanic sediments is crucial to evaluate the efficiency and stability of hydrate-based CO<sub>2</sub> sequestration in oceans. Here, systematic molecular dynamics simulations are executed to investigate the growth and dissociation of CO<sub>2</sub> hydrates, and the mechanical instability of CO<sub>2</sub> hydrate-Illite interface in the brine-urea-Illite system. Simulation results show that the CO<sub>2</sub> hydrate growth is jointly affected by the confined space, Illite surface properties, and presence of urea. Specifically, the interfacial H<sub>2</sub>O and the ion layer on the Illite surface hinder the growth of CO<sub>2</sub> hydrate crystals toward Illite surfaces. Urea molecules can bind salt ions and increase CO<sub>2</sub> concentrations in the water, thus kinetically promoting CO<sub>2</sub> hydrate growth. The dissociation of the CO<sub>2</sub> hydrate is affected by Illite surface properties and the CO<sub>2</sub> hydrate structure. CO<sub>2</sub> hydrate starts from the regions where hydrate particles are minimally in contact and extends on both sides. The mechanical tension and compression of the CO<sub>2</sub> hydrate-Illite interface exhibit nonlinear characteristics by changing the hydrogen bonds and the CO<sub>2</sub> hydrate structure. The molecular insight into the microscopic behavior of CO<sub>2</sub> hydrates in the brine-urea-Illite system contributes to a broader understanding of hydrate-based CO<sub>2</sub> sequestration.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":null,"pages":null},"PeriodicalIF":3.3000,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"The Journal of Physical Chemistry C","FirstCategoryId":"1","ListUrlMain":"https://doi.org/10.1021/acs.jpcc.4c05413","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Knowledge of the microscopic behavior of CO2 hydrates in oceanic sediments is crucial to evaluate the efficiency and stability of hydrate-based CO2 sequestration in oceans. Here, systematic molecular dynamics simulations are executed to investigate the growth and dissociation of CO2 hydrates, and the mechanical instability of CO2 hydrate-Illite interface in the brine-urea-Illite system. Simulation results show that the CO2 hydrate growth is jointly affected by the confined space, Illite surface properties, and presence of urea. Specifically, the interfacial H2O and the ion layer on the Illite surface hinder the growth of CO2 hydrate crystals toward Illite surfaces. Urea molecules can bind salt ions and increase CO2 concentrations in the water, thus kinetically promoting CO2 hydrate growth. The dissociation of the CO2 hydrate is affected by Illite surface properties and the CO2 hydrate structure. CO2 hydrate starts from the regions where hydrate particles are minimally in contact and extends on both sides. The mechanical tension and compression of the CO2 hydrate-Illite interface exhibit nonlinear characteristics by changing the hydrogen bonds and the CO2 hydrate structure. The molecular insight into the microscopic behavior of CO2 hydrates in the brine-urea-Illite system contributes to a broader understanding of hydrate-based CO2 sequestration.
了解海洋沉积物中二氧化碳水合物的微观行为对于评估海洋中基于水合物的二氧化碳封存的效率和稳定性至关重要。在此,我们进行了系统的分子动力学模拟,以研究二氧化碳水合物的生长和解离,以及盐水-尿素-沸石体系中二氧化碳水合物-沸石界面的力学不稳定性。模拟结果表明,二氧化碳水合物的生长受到密闭空间、伊利石表面特性和尿素存在的共同影响。具体来说,界面 H2O 和伊利石表面的离子层阻碍了 CO2 水合物晶体向伊利石表面的生长。尿素分子可以结合盐离子,增加水中的二氧化碳浓度,从而在动力学上促进二氧化碳水合物的生长。CO2 水合物的解离受伊利石表面特性和 CO2 水合物结构的影响。二氧化碳水合物从水合物颗粒接触最少的区域开始,向两侧延伸。通过改变氢键和 CO2 水合物结构,CO2 水合物-伊利石界面的机械拉伸和压缩表现出非线性特征。对盐水-尿素-沸石体系中二氧化碳水合物微观行为的分子洞察有助于更广泛地理解基于水合物的二氧化碳封存。
期刊介绍:
The Journal of Physical Chemistry A/B/C is devoted to reporting new and original experimental and theoretical basic research of interest to physical chemists, biophysical chemists, and chemical physicists.