Isotherms and thermodynamics for the adsorption of n-butane on pitch based activated carbon

The adsorption isotherms of n-butane on pitch based activated carbon (type Maxsorb III) at temperatures ranging from 298 to 328 K and at different equilibrium pressures between 20 and 300 kPa have been experimentally measured by a volumetric technique. The porous properties such as, the density, Brunauer-Emmett-Teller (BET) surface area, pore size, pore volume along with pore size distribution (PSD) of Maxsorb III have been determined. The Dubinin-Astakhov (DA) adsorption isotherm model describes all of the isotherm experimental data within the acceptable error ranges. The present isotherm data are compared with other published data of activated carbon (AC)/n-butane and showed the superiority of the present findings in terms of uptake capacity. The isosteric heat of adsorption (Delta H-ads) of n-butane on Maxsorb III is calculated for different loading. Using the adsorption isotherms and Delta H-ads, the thermodynamic property maps as a function of pressure, temperature and adsorbate amount are also presented. (C) 2007 Elsevier Ltd. All rights reserved.