ZSM-5 membrane synthesis with organic-free mixtures

Abstract

Preparation of supported ZSM-5 membranes using a TPA-free synthesis gel was investigated. After exploring the effect of reaction mixture the composition SiO_2:0.0125Al_2O_3:0.2675Na_2O:46H_2O was selected for membrane synthesis. Membranes were prepared by hydrothermal reaction on asymmetric α-Al_2O_3 tubular supports. The membranes were characterized by scanning electron microscopy, EDS, X-ray diffraction and Ar and N_2 adsorption. Permeation measurements with single gas and mixtures yielded selectivities for H_2 over n-butane above 104 and those for O2 over N_2 were 9–10. Permeation was strongly activated with the activation energies increasing sharply with molecular sizes.

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