Adsorption isotherms of water vapor on natural clay were obtained gravimetrically by a flow technic at 30, 40, 50 and 60°C up to the saturation pressure. The equilibrium data were also correlated by some theoretical models. The modified BET model was the best. The magnitude of the heats and entropies for constant loadings is indicative of physical adsorption and shows that the state of adsorbed water tends to that of condensed vapor near the saturation.
L. Gannouni, M. Baguenne, A. Bellagi