The atomic model of carbon xerogel microporous structure is reconstructed by a modified virtual porous carbon (VPC) model. The physical parameters of the reconstructed model, especially the predicted nitrogen adsorption isotherm, agree well with the experimental data. Then, the adsorption and diffusion of the gas in carbon xerogel microporous structure are investigated at the pore-scale. The results show that decreases of isosteric adsorption heat and the excess adsorption in carbon xerogel microporous structure are majorly contributed by the desorption of adsorbates in ultramicropores with the temperature increasing. The microporous structure appears a strong selectivity for oxygen in the air, due to the molecular sieving effect and the strong solid-fluid interaction between the pore wall and oxygen. As the desorption of oxygen in ultramicropores due to its increasing steric repulsion with the temperature rising from 298 K to 573 K, the selectivity of microporous structure for oxygen decreases, and the gap between isosteric adsorption heat for nitrogen and oxygen is narrowed. The systemic migration of gas molecules from the ultramicropores to the wider area is observed by the pore-scale analysis, and it makes the gas diffusivity appear an approximately linear relationship with the temperature.

通过改进的虚拟多孔碳（VPC）模型重建了碳干凝胶微孔结构的原子模型。重建模型的物理参数，尤其是预测的氮吸附等温线与实验数据吻合良好。然后，在孔隙尺度上研究了气体在碳干凝胶微孔结构中的吸附和扩散。结果表明，随着温度的升高，等量吸附热的减少和碳干凝胶微孔结构中的过量吸附主要是由于超微孔中吸附物的解吸作用。由于分子筛分效应和孔壁与氧气之间强烈的固液相互作用，微孔结构对空气中的氧气具有很强的选择性。随着温度从 298 K 升高到 573 K，氧在超微孔中的解吸由于其空间排斥力增加，微孔结构对氧的选择性降低，氮和氧的等量吸附热之间的差距缩小。孔隙尺度分析观察到气体分子从超微孔向更广阔区域的系统迁移，使气体扩散率与温度呈现近似线性关系。