Characterization of porous carbonaceous sorbents using high pressure CO2 adsorption data

In this paper we present adsorption isotherms of carbon dioxide on five different activated carbons from CHEMVIRON CARBON Belgium (Centaur HSV, BPL 410, F30-470, WS 42, Reactivated) and on a carbon molecular sieve from BERGBAU FORSCHUNG Gmbh (CMS II), The temperature is 303 K and the pressure ranges from 100 kPa up to 4000 kPa. Such conditions correspond to relative pressures ranging from 0.01 to 0.5. We also provide, for the same six sorbents, the nitrogen isotherms at 77 K (pressure: 0.001 to 100 kPa, relative pressure. 10(-5) to 1). A theoretical treatment based on the Dubinin-Radushkevich and Stoeckli concept is presented and applied to the experimental results in order to obtain the micropore site distribution function (considered as Gaussian) of each sorbent. Using the CO2 data, it is possible to point out important structural differences between the six carbons. The theoretical treatment provides micropore size distribution functions in agreement with what is physically expected. Using N-2 data, the structural differences are not so well marked. As a consequence, the structural parameters provided by the theoretical treatment are not reliable. except for the total micropore volume, they fluctuate strongly when changing the relative pressure domain of the used data.