氮气和氧气在膜表面和狭缝孔内平衡吸附的分子模拟

采用巨正则系综的MonteCarlo方法(GCMC)模拟常温(T=303K)下,氮气和氧气在具有狭缝状膜孔的碳膜内的吸附.气体分子之间、气体分子与膜原子之间的相互作用均采用Shifted-Lennard-Jones势能模型.研究了303K和10MPa下,不同膜厚度和膜孔宽度时氧气在膜面和膜孔内的密度分布以及303K和压力从1MPa到10MPa变化时,氮气和氧气在狭缝膜孔内超额吸附等温线.实验结果表明,膜孔端口效应显著,膜厚和膜孔宽度对孔内吸附影响较大,而膜构型对膜面吸附影响显著.

Molecular Simulation of Equilibrium Adsorption of Nitrogen and Oxygen both in Slit Pore and on Membrane Surface

Monte Carlo molecular simulation is employed to investigate the equilibrium adsorption of nitrogen and oxygen in the slit pore and on the carbon membrane surface.The interactions among all kinds of molecules are modeled with Shifted-Lennard-Jones potential.The results obtained display the oxygen density distribution both in the slit pore and on the membrane surface varying with the change of pore width and membrane length at 303 K and 10 MPa.The excess adsorption isotherms(which measure the increased density in the slit pore,relative to that of the bulk fluid) per unit volume of both nitrogen and oxygen at 303 K show a maximum at a particular value of the pressure.The principal conclusions of this work are as follows:(1) the entrance-pore effect on the density distribution of gas in the slit pore is distinct;(2) the excess adsorption in the pore increases with the decrease of slit pore width;(3) the membrane model plays a significant role in the excess adsorption on the membrane surface.