Dielectric Properties of Dehydrated Zeolites

The synthetic zeolites of Heulandite group were prepared using Microwave-Hydrothermal (M-H) method at 120 ° C/30 min. The powders were characterized using X-ray Diffraction (XRD).The Zeolites were annealed at 60, 80 and 100 o C/1 hr. The d.c resistivity of Heulandite group zeolite was found to be constant upto 378K and increased as the temperature increases. Dielectric spectras (ε ’ and tanδ) of dehydrated zeolites were measured in the temperature range (333 373K) over a frequency range (1kHz – 1MHz).It has been observed that there were two loss peaks (two relaxations) and both peaks shifted to higher frequency on raising the temperature indicating that two relaxations are thermally activated processes. It was found that dielectric constant decreases with an increase of frequency. It has been observed that there were two loss peaks (two relaxations) and both peaks shifted to higher frequency on raising the temperature indicating that two relaxations are thermally activated processes. The d.c resistivity measurement has been carried out using two probe method upto 403K. The d.c conductivity of Heulandite group zeolite was found to be constant upto 378K and increased as the temperature increases. Keywords— M-H synthesis, Zeolites, Dielectric Properties, d. c resistivity.