Abstract
Adsorption behavior of toluene on activated carbon in the presence of carbon dioxide was measured at 10.0 and 15.0 MPa from 313 to 353 K. The amount of adsorbed toluene increased with increasing temperature and decreasing pressure, which indicated strong density effects of carbon dioxide. Langmuir model was applied to correlate the amount of adsorbed toluene for various mole fractions at each isothermal and isobaric condition, and the Langmuir constants decreased with increasing carbon dioxide density. A mathematical model was applied for describing adsorption kinetics by considering the equilibrium, diffusion in the solid, axial dispersion and mass transfer from bulk of the fluid phase to surface of the solid. The model could represent the experimental data with one fitting parameter which is effective diffusion coefficient of toluene in the pores. Additionally, the effective diffusion coefficient strongly depended on the carbon dioxide density, which implied a possibility that the breakthrough curves could be predicted at various conditions.
