A DIELECTRIC STUDY OF SYNTHETIC LINDE TYPE-A ZEOLITE .3. DIELECTRIC PROPERTIES OF 3-A J-A AND AG-A WITH ADSORBED WATER

The permittivity and dielectric loss factor for the Molecular Sieve Zeolites type 3-A and 4-A and a silver exchange form of type-A have been measured in the frequency range 5 Hz to 140 MHz with various amounts of adsorbed water present. A region of dielectric loss in all three may be attributed to movement, within the cavities, of the interstitial cations. The activation energy for the process varies with water content and at any one water content a linear relationship exists between the activation energies and the size of the cations concerned. The behaviour of the activation energy with temperature suggests some change of phase of the adsorbed water takes place, equivalent to freezing, at a temperature well below 0°C. A further region of dielectric absorption has been observed which has been attributed to relaxation, with an ice-like character, of the major part of the adsorbed water dipole moment. The remainder of the water dipole relaxing by motions, other than complete reorientation, at higher frequencies than those available in the present study. © 1969.