ELECTRICAL INVESTIGATION OF THE WATER ADSORPTION MECHANISM ON NATURAL CLINOPTILOLITE
Zeolites are ionic conductors and the cation electrical mobility in zeolites depends on their hydration state; consequently, the water adsorption/desorption process can be simply investigated by measuring the temporal evolution of current intensity in samples exposed to an environment with constant humidity or dry air, respectively. According to this kinetic analysis, a mechanism has been formulated for the water adsorption process able to justify the Lagergren pseudo-first-order kinetics observed for adsorption and the first-order kinetics observed for desorption. In this mechanism water molecules are first attract by the electric field of the cations and then they move at cation-framework interface to maximize the hydrogen bond interactions.