Influence of density and water vapor content on the dielectric response of natural zeolites

Dielectric spectra of natural zeolite (clinoptilolite) are studied in a wide range of pressures from 10(-2) Torr up to atmospheric pressure and the absorption IR spectra of clinoptilolite (Cl) have been investigated from 4000 to 400 cm(-1). The measurements were carried out on samples of high density (natural plate) and low density (unpressed powder). It is established that the frequency dependence of both real and imaginary parts of the,dielectric permittivity is characterized by approximately the same relaxation time of about 10(-5) s. It is concluded that in all these cases, the dielectric spectra are determined by fluctuations of alkali-metal ions associated with the water molecules inside the zeolite pores. A difference in the corresponding dielectric spectra is related to the concentration of these complexes. In the IR spectra, it is established that the presence of coordinating water and its large width evidences on localization of (OH) groups in the channels.