State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, School of Renewable Energy, North China Electric Power University, Beijing, 102206, China.
State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, School of Renewable Energy, North China Electric Power University, Beijing, 102206, China.
J Mol Graph Model. 2018 Aug;83:84-91. doi: 10.1016/j.jmgm.2018.05.005. Epub 2018 May 21.
Understanding the adsorption behaviors of supercritical fluid in confined space is pivotal for coupling the supercritical technology and the membrane separation technology. Based on grand canonical Monte Carlo simulations, the adsorption behaviors of a Lennard-Jones (LJ) fluid in slit-like pores at reduced temperatures over the critical temperature, T = 1.312, are investigated; and impacts of the wall-fluid interactions, the pore width, and the temperature are taken into account. It is found that even if under supercritical conditions, the LJ fluid can undergo a "vapor-liquid phase transition" in confined space, i.e., the adsorption density undergoes a sudden increase with the bulk density. A greater wall-fluid attractive potential, a smaller pore width, and a lower temperature will bring about a stronger confinement effect. Besides, the adsorption pressure reaches a local minimum when the bulk density equals to a certain value, independent of the wall-fluid potential or pore width. The insights in this work have both practical and theoretical significances.
理解超临界流体在受限空间中的吸附行为对于将超临界技术与膜分离技术相结合至关重要。本文基于巨正则蒙特卡罗模拟，研究了在临界温度以上的减小温度下，Lennard-Jones（LJ）流体在狭缝状孔中的吸附行为，并考虑了壁流相互作用、孔径和温度的影响。结果表明，即使在超临界条件下，LJ 流体也可以在受限空间中经历“汽-液相变”，即吸附密度随本体密度的增加而突然增加。更强的壁流吸引势、更小的孔径和更低的温度会产生更强的约束效应。此外，当本体密度等于某个值时，吸附压力达到局部最小值，与壁流势或孔径无关。这项工作的见解具有实际和理论意义。
