纳米孔内的吸附过程及其动力学特性研究
Molecular Dynamics Simulation of Adsorption and Kinetic Analysis in Nanopore
何转桃 1吴春梅 1李友荣1
作者信息
- 1. 重庆大学低品位能源利用技术及系统教育部重点实验室,能源与动力工程学院,重庆 400044
- 折叠
摘要
为了阐明气体在纳米多孔结构内的吸附及动力学过程,采用分子动力学方法建立了纳米多孔材料的吸附与解吸模型,探究了氩气在多孔结构表面的吸附特性,并对其吸附与解吸的动力学特性进行了分析.结果表明:纳米孔内的吸附机制有两种:一是吸附层生长过程中,相对壁面的吸附层不断靠近后孔内发生的液体桥接.二是孔隙内发生毛细管凝结后引起的弯月面推进.低压比时,吸附层持续增长,压比增加时孔隙内观察到液体桥接效应,由于液膜表面不稳定出现液桥的生长与收缩断裂;高压比时,纳米孔入口附近形成稳定的液桥,孔隙内出现空腔,空腔内的快速吸附可导致液体的二次桥接,这种现象不断重复直至空腔被填满.另外,解吸过程是在弯月面后退和空化作用下进行的.
Abstract
Molecular dynamics simulations have been employed to explore the adsorption and des-orption process of the gas in nanopore,and their dynamic properties have been analyzed.It is shown that there are two adsorption mechanisms in nanopore:one is the liquid bridging which occurs when the adsorption layer on the opposite wall is close to each other;The other is the meniscus advance due to capillary condensation.As the pressure ratio increases,the bridging effect of the liquid was observed,and the instability of the liquid film surface led to the growth and shrinkage of liquid bridge.At the higher pressure ratios,a stable liquid bridge is formed near the entrance of the nanopore,formation and collapse of nanobubble were observed in nanopore.The rapid adsorption and condensation of the nanobubble leads to a secondary bridging of the liquid,which is repeated continuously until the bubble collapses.In addition,it was observed that the desorption process is governed by the combination of cavity cavitation and thinning of the adsorption layer.
关键词
纳米孔/吸附/解吸/动力学/液桥Key words
nanopore/adsorption/desorption/kinetic characterization/liquid bridge引用本文复制引用
出版年
2024
NETL
NSTL
维普
万方数据