Hierarchy Control of MFI Zeolite Membrane towards Superior Butane Isomer Separation Performance

Microstructural optimization (such as thickness and preferred orientation) is a major concern for performance enhancement of zeolite membranes. In this study, we demonstrated that the introduction of hierarchy easily enabled concurrent thickness reduction and orientation control of zeolite membranes. Specifically, hierarchical MFI zeolite membranes comprising higher degree of (h0h) preferentially oriented ultrathin (ca. 390 nm) selective top layers and porous intermediate layers on porous alpha-Al2O3 substrates were fabricated. The use of hollow-structured MFI nanoseeds and the employment of single-mode microwave heating during membrane processing were found indispensable for the preparation of MFI zeolite membranes with superior butane isomer separation performance, thereby surpassing the current n-/i-butane selectivity versus n-butane permeance trade-off limits of MFI zeolite membranes prepared via solution-based synthetic protocols.

Automated summary

Introducing hierarchy enables concurrent thickness reduction and orientation control of zeolite membranes, leading to enhanced performance. Hollow-structured MFI nanoseeds and single-mode microwave heating are crucial for preparing superior butane isomer separation performance of MFI zeolite membranes.