Study of the active carbon-water interaction by flow adsorption microcalorimetry

The adsorption of water vapor by active carbons was studied using flow adsorption microcalorimetry, and data concerning the dependence of the heat evolution on the amount adsorbed were obtained. At small uptakes of adsorbate, the molar heat of adsorption is high indicating chemisorption and the molar heat decreases sharply with the amount sorbed and reaches a value close to that of the heat of condensation of water. The measurements also indicate the occurrence of exothermic rearrangements of the porous structure of the carbon induced by the adsorption forces.