Properties of dielectrics and microwave heating of zeolites with different framework structures -measurements and theoretical study

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It has been suggested so far that cations on the site III in zeolite A show unusual dielectric properties and strongly affect properties of microwave heating. In order to confirm this suggestion, dielectric properties of zeolites (Na_<12>-A and K_<12>-A) with cation on the site III and zeolites (Na_<10>Ca_1-A, Na_8Ca_2-A, Na_4a_4-A and K_<10>Ca_1-A) without that were studied. The former showed lower activation energies of cation motion and the latter higher energies. Absorption efficiencies of zeolites for microwaves were calculated by using the dielectric properties. The former had a higher efficiency than the latter. The former was easily heated by, microwave radiation and reached higher temperature than the latter. Since the calculated properties for microwave heating were in good agreement with he properties measured, the calculation method used was judged valid.The same method was applied to zeolites with different framework structures (zeolite A, L and mordenite). (In the followi … More ngs, zeolite A, L and mordenite are written as -A, -L and -M, respectively.) Absorption efficiencies for microwaves were calculated and were in the order of Na_<12>-A>Na_6K_6-A>Na_<4.3>-M>Na_<10>Ca_1-A>K_9-L>Na_4Ca_4-A On the other hand, final heating temperatures measured were in the order of Na_<12>-A>Na_<4.3>-M>Na_6K_6-A>K_9-L>Na_<10>Ca_1-A>Na_8Ca_2-A>Na_4Ca_4-A. There were two disagreement points in the orders, which are, underlined. The disagreements appeared in the points which are between zeolites with different framework structures. There is a large difference in structural density among these zeolites studied. A correction for the density was made to the absorption efficiencies. The absorption efficiencies were improved after correction but the discrepancies between the calculation and measurements remained still.It is found from the results that the present theoretical method can validly expect the microwave heating properties in the comparison with the identical kind of zeolite but may bring about some discrepancy in the comparison with the different kinds. Less