Computer Simulations for Adsorption of Benzene Diluted in Supercritical Carbon Dioxide

Abstract

The NVT and μVT ensemble MC techniques have been used for simulations of adsorptions in a slitpore from a binary mixture of benzene diluted in supercritical CO₂. The LJ potential function is used for representing intermolecular interactions between CO₂, benzene and surface carbon. A typical curve for adsorption of benzene shows a maximum at a pressure below the critical pressure of CO₂ and then decreases with increasing pressure. The magnitude of maximum adsorption increases with increasing interaction energy between benzene and surface carbon. It has been shown that this adsorption behavior is attributable mainly to enhanced solubility in the supercritical CO₂ and partly to the competitive adsorption of CO₂. The adsorption of carbon dioxide increases linearly with pressure and the slit pore becomes full of CO₂ molecules under supercritical fluid conditions. The local density profile of benzene in a pore is scarcely affected by CO₂; however, the profile of CO₂ is strongly affected by benzene molecules when they occupy the first monolayer near the wall.