Theoretical Study of Adsorption on Activated Carbon from Supercritical Fluid by SLD-ESD Approach

In this paper, the simplified local density (SLD) theory is combined with the ESD equation of state to study the adsorption of solutes from supercritical carbon dioxide onto activated carbon. Firstly the model was applied to fit the adsorption of toluene+CO2 and benzene+CO2 by using only two temperature-independent parameters. It was shown that this theoretical model is capable of describing the adsorption behavior for toluene and benzene on activated carbon from supercritical carbon dioxide over wide temperature and pressure ranges. Secondly we present a systematic theory analysis of adsorption characteristics for finite and infinite dilution conditions in supercritical fluid by selecting the toluene/CO2 as a model system. The characteristics of the competition adsorption on adsorbent between solvent and solute were investigated. The effect of temperature, pressure, bulk solute concentration, and the adsorbent structure size on the adsorption behavior has been presented.