Multicomponent (Binary and Ternary) Adsorption Equilibria of Volatile Organic Compounds (Acetone, Toluene, and n-Hexane) on Activated Carbon in Supercritical Carbon Dioxide

The multicomponent (binary and ternary) adsorption equilibria of three volatile organic compounds (VOCs) (acetone, toluene, and n-hexane) on activated carbon were studied under supercritical carbon dioxide (scCO₂) conditions. The multicomponent adsorption equilibrium data were obtained at 313-353 K and 4.2-10.0 MPa and depended on the affinities of the adsorbates for the adsorbent. The amounts of adsorbed VOCs decreased with increases in the pressure and decreases in the temperature, owing to the effects of the CO₂ density. The measured adsorption equilibria were correlated within 5.5% of the average relative deviation to the Dubinin-Astakhov equation using two parameters. These parameters, which were determined based on these correlations, provided information on the multicomponent adsorption equilibria of the VOCs under scCO₂ conditions while considering the interactions between the VOCs and the adsorbent, the bulk phase CO₂ density, and the competitive adsorption of the VOCs and CO₂ in the adsorbed phase.