WATER-ADSORPTION IN ACTIVE CARBONS DESCRIBED BY THE DUBININ-ASTAKHOV EQUATION

It is shown that the adsorption of water by a variety of active carbon s can be described within the framework of Dubinin's theory. Owing to the low values of the characteristic energy, E (0.8-2.5 kJ mol-1), the Dubinin-Astakhov equation becomes S-shaped in the range 0.3 < p/p(o) < 0.7 and provides a good basis for the fit of the adsorption branch o f type V isotherms near room temperature. The parameters of the equati on are almost temperature invariant and consequently a good agreement is also found in many cases for the enthalpies of immersion into water , as predicted by the extension of Dubinin's theory.