The isotherms for the adsorption of water vapor on graphitized carbon black and graphite have been studied in
a number of works (see for example [8-10, 12-14]); they have been studied in detail in [10]: It was shown that the
adsorption of water on graphitized carbon black is negligibly small, the isotherm is concave throughout the whole
range of relative pressures P/Ps and even at values of P/Ps close to unity a compact monolayer is not formed. This
was attributed to a particularly weak bond between the water molecules and the graphite surface. The differential
heat of adsorption of water on graphitized channel black was studied in [13, 14], and contradictory data were obtained.
In [13], high negative values were obtained for the pure beat of adsorption, like the heats of adsorption of water on
carbon, determined in [15].