The adsorption of a single-solute from dilute aqueous solutions by active carbons has been formulated in terms of the corresponding vapor phase adsorption parameters and the ''interfacial'' similarity coefficient, which characterizes the similarities between the adsorption curves for the gas/solid and solid/liquid interfaces. Subsequently, these equations have been used to characterize the microporosity of eight different active carbon samples on the basis of benzene adsorption isotherms measured from dilute aqueous solutions. It has been demonstrated on the basis of the experimental adsorption isotherms that liquid/solid data provide essentially the same information about the structural heterogeneity of porous carbons as that obtained via gas/solid adsorption measurements.