Reference isotherm for high pressure adsorption of CO₂ by carbons at 273 K

It is suggested that the adsorption of CO₂ on Vulcan 3G at 273 K and up to 3.2 MPa can be used as a reference isotherm for the characterization of porous and non-porous carbons. The results obtained with the proposed reference are in good agreement with those of the nitrogen (77 K) and benzene (293 K) comparison plots. The external surface areas have also been compared with those obtained from immersion calorimetry into C₆H₆ at 293 K. It also appears that at low relative pressures CO₂ adsorbed on Vulcan 3G follows the Dubinin–Radushkevich–Kaganer equation between 253 and 273 K.