The phenomenon of adsorption-induced deformation of nanoporous materials has recently attracted a lot of attention in chemical, materials, and geoscience communities. Various theoretical and molecular simulation approaches have been suggested to predict the stress and strain induced by single component gas adsorption. Here, we develop a thermodynamic method based on the notion of the adsorption stress to predict the deformation effects upon multicomponent adsorption. As a practically important example, the process of the displacement of methane by carbon dioxide from microporous carbons is considered. This process is the foundation of secondary gas recovery from shales and coalbeds associated with carbon dioxide sequestration. Theoretical predictions are correlated with the original experimental data on CO₂ and CH₄ individual and binary adsorption on coal samples coupled with in situ strain measurements. With the model parametrized and verified against the experimental data at ambient temperature, the projections are made for the adsorption deformation at geological conditions of elevated pressure and temperature, which increase with the depth of the reservoir. The proposed approach may have multifaceted applications in modeling the behavior of hydrocarbon mixtures in nanoporous geomaterials, gas separations, and energy storage on flexible adsorbents.

中文翻译：

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二元吸附过程中纳米多孔材料的变形：煤中二氧化碳置换甲烷

纳米多孔材料的吸附诱导变形现象最近引起了化学、材料和地球科学界的广泛关注。已经提出了各种理论和分子模拟方法来预测由单组分气体吸附引起的应力和应变。在这里，我们开发了一种基于吸附应力概念的热力学方法来预测多组分吸附的变形效果。作为一个实际重要的例子，我们考虑了用二氧化碳从微孔碳中置换甲烷的过程。该过程是从与二氧化碳封存相关的页岩和煤层中二次采气的基础。理论预测与 CO ₂的原始实验数据相关煤样品上的CH ₄单独和二元吸附与原位应变测量相结合。通过模型参数化和常温实验数据验证，对随着储层深度增加而增加的压力和温度升高的地质条件下的吸附变形进行了预测。所提出的方法可能在模拟纳米多孔地质材料中碳氢化合物混合物的行为、气体分离和柔性吸附剂上的能量存储方面具有多方面的应用。