<報文>アンモニア分解法により製造した水素型ゼオライトの加熱変化およびイオン交換特性

概要

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Thermal transformation and ion exchange property were studied in various kinds of H-formed zeolites-synthetic zeolites A, X and Y, synthetic mordenite, natural mordenite and clinoptilolite. H-formed zeolites were produced by the thermal decomposition of NH_4-formed zeolites. The thermal decomposition of NH_4-formed zeolites was studied by using infrared, differential thermal analyses and X-ray powder diffraction. Deammoniation occurred in the temperature range of 350〜500℃ followed by hydroxylation, and dehydroxylation took place in the wide temperature range of 500〜900℃. These reactions overlapped one another to a considerable extent. H-formed zeolites recrystallized to cristobalite and mullite at a temperature above 900℃ for A, X and Y zeolites, and above 1000℃ for mordenites and clinoptilolite. The distribution coefficient of cesium (K_<Cs>) decreased with increasing acidity, though the K_<Cs> values for H-formed synthetic mordenite (HSM) attained about 10^4 in the acidic region (pH 1〜3). As for strontium, the K_<Sr> values for A, X and Y attained about 10^4 in the neutral region, but markedly decreased with the increase in acidity. HSM produced by heat treatment below 400℃ in air and below 350℃ in a vacuum had a good break-through property.
東北大学の論文
1980-09-30