Due to their great potential in membrane separation and catalytic membrane reactors, considerable research effort has been applied to the b-oriented MFI zeolite membrane. The latest developments of secondary growth strategies of b-oriented MFI zeolite membrane are reviewed in this paper. In particular, the effects of important factors on preparing b-oriented MFI films, such as synthesis of seeds, seed-coating methods and synthetic solution compositions, are summarized in detail. The advantages and disadvantages of these synthetic strategies, and their influences on the separation performance(separation factor and permeance) and catalytic performance of synthesized MFI zeolite membranes are evaluated. This review also introduces the latest breakthroughs in monitoring and controlling growth of two-dimensional(2D) zeolite crystal, and bottom-up syntheses of membranes with ultra high selectivity and flux from zeolite nanosheets produced in situ. Based on the extensive discussion of various preparation strategies, the developing trends in the preparation of b-oriented MFI zeolite membrane are forecasted.
Contents
1 Introduction
2 Progress in synthesis of zeolite seeds
3 Progress in coating methods
3.1 Manual assembly
3.2 Air-water interfacial assembly
3.3 Other coating methods
4 Progress in secondary growth
4.1 Prevention of the attachment between seeds and (0k0) face
4.2 Change of mineralizing agents
4.3 Improvement of secondary growth synthesis solution composition
4.4 Ultra-selective ultra-flux zeolite membrane
5 Conclusion and outlook