Theoretical study of adsorption on activated carbon from a supercritical fluid by the SLD–ESD approach

The simplified local density (SLD) theory is combined with the Elliott, Suresh, Donohue (ESD) equation of state to model adsorption of solutes from supercritical carbon dioxide onto activated carbon. The model is fit to adsorption isotherms of toluene + CO2 and benzene + CO2 over wide temperature and pressure ranges by adjusting only two temperature-independent parameters for each binary. We present a systematic analysis of adsorption characteristics for finite and infinite dilution conditions in supercritical CO2 by selecting the toluene/CO2 as a model system. Competitive adsorption between solvent and solute is investigated. The effects of temperature, pressure, bulk solute concentration, and the adsorbent structure size on the adsorption behavior are presented.