Influence of T atom nature on morphology and crystal size of KZ-2 and ZSM-22 zeolites isomorphously substituted with Al or Fe.

摘要

Syntheses of KZ-2 and ZSM-22 zeolites isomorphously substituted with iron or aluminiumwere carried out for a wide range of the Si/T ratio (T=Al, Fe). Effect of the gel compositionon size and morphology of the crystals formed was studied. It was shown that usingdiethylamine as a template it was possible to synthesize crystals of the iron containing KZ-2zeolites similar in size and morphology, independently of the Si/Fe ratio in the gel. No sucheffect was observed when the syntheses were carried out in the presence of aluminium. Forthe ZSM-22 zeolite, synthesized in the presence of 1-ethylpyridinium bromide as template,both aluminium and iron analogues showed strong dependence of texture of the crystalsformed on the Si/T ratio. The results point to an important role of nature of the T cations in the process of the zeolite crystal growth.