Adsorption of water vapor on active carbon preadsorbed with methanol and benzene

Adsorption isotherms of water vapor on active carbon preadsorbed with small amounts of methanol and benzene are measured and the influence of the preadsorbates on the following water vapor adsorption is discussed, in terms of the number of primary adsorption centers a(0) for water vapor adsorption by the Dubinin-Serpinsky equation. Methanol preadsorption decreases the values of a(0), while benzene does not. The results show that methanol is adsorbed on the edges of the micropore walls, where oxygen-surface complexes exist and the adsorption space for water in micropores is maintained, while benzene is adsorbed on the basal planes, which diminishes the adsorption space for water vapor in micropores. (C) 1997 Academic Press.