Bai Dongsheng, Chen Guangjin, Zhang Xianren, Sum Amadeu K, Wang Wenchuan
1] Department of Chemistry, School of Science, Beijing Technology and Business University, Beijing, 100048, P. R. China [2] Division of Molecular and Materials Simulation, State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, P. R. China.
State Key Laboratory of Heavy Oil Processing, School of Chemical Engineering, China University of Petroleum, Beijing, 102249, P. R. China.
Sci Rep. 2015 Jul 31;5:12747. doi: 10.1038/srep12747.
Molecular dynamics simulations were performed for CO2 dissolved in water near silica surfaces to investigate how the hydrophilicity and crystallinity of solid surfaces modulate the local structure of adjacent molecules and the nucleation of CO2 hydrates. Our simulations reveal that the hydrophilicity of solid surfaces can change the local structure of water molecules and gas distribution near liquid-solid interfaces, and thus alter the mechanism and dynamics of gas hydrate nucleation. Interestingly, we find that hydrate nucleation tends to occur more easily on relatively less hydrophilic surfaces. Different from surface hydrophilicity, surface crystallinity shows a weak effect on the local structure of adjacent water molecules and on gas hydrate nucleation. At the initial stage of gas hydrate growth, however, the structuring of molecules induced by crystalline surfaces are more ordered than that induced by amorphous solid surfaces.
对溶解在二氧化硅表面附近水中的二氧化碳进行了分子动力学模拟，以研究固体表面的亲水性和结晶度如何调节相邻分子的局部结构以及二氧化碳水合物的成核过程。我们的模拟结果表明，固体表面的亲水性可以改变液固界面附近水分子的局部结构和气体分布，从而改变气体水合物成核的机制和动力学。有趣的是，我们发现水合物成核在相对亲水性较低的表面上更容易发生。与表面亲水性不同，表面结晶度对相邻水分子的局部结构和气体水合物成核的影响较弱。然而，在气体水合物生长的初始阶段，晶体表面诱导的分子结构比非晶固体表面诱导的更有序。
