CHARACTERIZING THE MICROPORE SIZE DISTRIBUTION OF ACTIVATED CARBON USING EQUILIBRIUM DATA OF MANY ADSORBATES AT VARIOUS TEMPERATURES

In this paper, we present an approach to characterize the micropore si ze distribution (MPSD) of activated carbon by using multiple-temperatu re isotherm data of many adsorbates simultaneously. The characteristic s of the model are as follows: (1) The MPSD is treated as the intrinsi c property of activated carbon (independent of adsorbate) and the sole source of heterogeneity. (2) Different adsorbates have access to diff erent pore size ranges because of their difference in molecular sizes. (3) The adsorbate-adsorbent interaction energy is related to the micr opore size through the Lennard-Jones potential theory. This method is examined with the extensive equilibrium data of many adsorbates measur ed on two different activated carbons under a wide temperature range. The effects of the configuration of the slit-shaped micropores and the local adsorption isotherm are also investigated. It is shown that, wi th the intrinsic structural parameters, the model proposed can describ e very well the adsorption equilibria of different species on each act ivated carbon and predict reasonably well the multicomponent adsorptio n equilibria for a number of systems studied in this paper. The physic al significance of the results and the applicability of the model are also discussed.