Adsorption of Propane on a Supermicroporous Carbon Adsorbent with a Wide Pore Size Distribution under Conditions of Subcritical Temperatures

The adsorption of propane on an ACW supermicroporous adsorbent with a wide pore size distribution at pressures up to 1 MPa and temperatures of 303, 313, 323, and 333 K was studied. The maximum value of propane adsorption at a temperature of 303 K and a pressure of 1 MPa is equal to 21.6 mmol/g. The dependences of the differential molar isosteric heat of adsorption of propane on the value of adsorption are calculated. In the initial region of micropore filling of up to ~6 mmol/g, the heat of propane adsorption on the microporous adsorbent is practically constant (~27 kJ/mol). Then, as the micropores are filled, the heat of adsorption drops to 25 and 23 kJ/mol at temperatures of 303 and 333 K, respectively. Thereafter, a sharper drop in heat occurs to 20 kJ/mol at 20 mmol/g. As a result of calculations, the temperature dependence of heat on propane adsorption is obtained in the form of a fan of curves. The experimental data are compared with the results of calculations of propane adsorption based on Dubinin’s theory of volumetric filling of micropores using the structural and energy characteristics of the adsorbent.