MECHANISMS OF ADSORPTION OF CO2 IN THE MICROPORES OF ACTIVATED ANTHRACITE

The combined use of n-nonane preadsorption and CO2 adsorption at 273 K allows interpretation of the mechanism of adsorption of CO2 in narrow micropores of a series of CO2-activated carbons prepared from an anth racite. The mechanism depends on the shape and size of the pores. In n arrow micropores of molecular dimensions (1 sigma), CO2 is probably ad sorbed by micropore filling - as proposed for the adsorption of N-2 at 77 K - which is associated with curved CO2 isotherms at 273 K. With i ncreasing degree of activation, the microporosity widens and the adsor ption of CO2 in narrow micropores of supramolecular dimensions (>2 sig ma) probably occurs by surface coverage, which is associated with rect ilinear isotherms.