水环境下甲烷在不同润湿性石英表面吸附行为的分子动力学模拟

采用分子动力学模拟方法研究水环境下石英表面润湿性对甲烷在石英狭缝中吸附行为的影响。结果表明:对于亲水性较强的石英表面,水分子优先吸附于石英表面,甲烷分子在狭缝中心发生团聚;而疏水性较强的石英表面,甲烷分子优先吸附于石英表面,水分子在狭缝中心发生团聚;当石英表面为中性润湿时,石英表面对这两种分子没有表现出优先选择性吸附。水、甲烷与不同润湿性石英表面的相互作用能表明,水/固相互作用是水环境下甲烷在石英狭缝中吸附构型改变的主要驱动力。

Molecular dynamics simulation of methane adsorption with presence of water on different wettability quartz surface

Molecular dynamics (MD) simulation was performed to investigate the effect of surface wettability of quartz on the adsorption behavior of methane (CH₄) in the slit of quartz under water environment. The simulation results show that as to strong hydrophilic quartz surface, the water molecules adsorb on the quartz surface preferentially, while the CH₄ molecules aggregate at the center of the slit. When the quartz surface is strong hydrophobic, the CH₄ molecules adsorb on the quartz surface preferentially, while the water molecules aggregate at the center of the slit. However, when the quartz surface is intermediate wettability, the quartz surface has no preferential adsorption to water and CH₄ molecules. The interaction energy between water or CH₄ molecules and quartz surface with different wettability is calculated, respectively. The results show that the water/solid interaction is the main driving force for the methane adsorption on rocks surface under the water environment.