Fabrication of b‐Oriented MFI Zeolite Membranes by a Printing‐Transfer Seed Layer Procedure

A simple and easily scaled-up printing-transfer seed layer method was used to prepare b-oriented MFI seed layer on porous support. By using poly(hexamethylene biguanidine) hydrochloride (PHMB) as a twin crystal inhibitor, highly b-oriented MFI zeolite membranes were prepared with high separation performance.

Abstract

Highly b-oriented MFI zeolite (abbreviated as BOMZ) membranes are attractive due to less grain boundary defects and straight channels normal to the substrate, enhancing selectivity and flux in membrane separation. Herein, we demonstrate a novel, effective and easily-amplified printing-transfer oriented-seed-layer technique to manufacture uniform BOMZ seed monolayer on porous supports. Furthermore, a facile and effective approach for the synthesis of highly BOMZ membranes by introducing poly(hexamethylene biguanide) hydrochloride as a twin crystal inhibitor during seeded growth is demonstrated. Well-intergrown BOMZ membranes (∼650 nm thick) obtained on porous Al₂O₃ supports show a flux of 2.8 kg m⁻² h⁻¹ with a separation factor as high as 71 for pervaporation in the 60 °C feed of EtOH/H₂O (5 wt%), which is much higher than those of random membranes. The developed seed assembly technique on porous supports underlines great potential for facile preparation of oriented seed layers on porous supports.

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