VOCs (acetone, toluene, and n-hexane) adsorption equilibria on mesoporous silica (MCM-41) over a wide range of supercritical carbon dioxide conditions: Experimental and theoretical approach by the Dubinin–Astakhov equation

• Adsorption equilibria of acetone, toluene and n-hexane on mesoporous in supercritical CO2 were reported.
• Adsorption isotherms strongly depended on adsorbates, adsorbents and density of carbon dioxide.
• Measured data could be correlated with the Dubinin–Astakhov equation.
• The model provided quantitative information about the adsorption phenomena in supercritical CO2.

Adsorption equilibria of three volatile organic compounds (VOCs) (acetone, toluene, and n-hexane) on mesoporous silica (MCM-41) were investigated over a wide range of supercritical and pressurized carbon dioxide conditions. Measurements of the adsorption equilibria were performed with a fixed bed method at temperatures from 313 to 353 K and pressures from 4.2 to 15.0 MPa. The measured adsorption equilibria strongly depended on properties of VOCs, which could be explained by the affinity between the adsorbent and adsorbate. The Dubinin–Astakhov equation demonstrated satisfactory correlations of the adsorption equilibria within 10% of average relative deviation. Two fitting parameters determined with the equation provided quantitative information on adsorption phenomena in considerations of the VOCs affinity to the adsorbents, CO2 density, and pore structure of adsorbents.

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