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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. [ABSTRACT FROM AUTHOR]

• No drying process is needed before direct secondary growth and after seeding. • No pore plugging process with low concentration nutrients or water is needed. • The current method can reduce the formation of crystals in the support pores. • The highest flux is obtained among membranes on similar tubular supports. NaA zeolite membranes were first applied in industrial organic solvent dehydration in 1999. However, issues such as poor reproducibility, low flux, and high cost of NaA zeolite membrane preparation have hindered its industrial progress. In this work, a direct secondary growth of wet gel layer method is employed. Specifically, a wet gel layer is coated to the outer surface of the seeded support, which is then placed into the Teflon-lined autoclave without additional hydrogel inside. Under the conditions of conventional secondary growth (100 °C for 4 h), high flux NaA zeolite membranes can be prepared. The pervaporation performance in the 90 wt% ethanol/water solution is tested at 75 °C, showing the flux up to 4.59 kg m−2 h−1 and the separation factor above 10,000. The controlling factors involved in the preparation of high flux NaA zeolite membranes using the direct secondary growth of wet gel layer are investigated. It is found that the introduction method of the seed layer and wet gel layer, the size of the seed, the state of the gel, and the immersion time play significant roles in the formation of zeolite membranes with superior separation performance. This method provides a new idea for the preparation of high performance, low cost and reproducible zeolite membranes with prospects for industrial application. [ABSTRACT FROM AUTHOR]

Weakening the mass transfer resistance inside the selective layer of membrane can effectively increase the membrane separation performance. In this study, we introduce macropores into the conventional LTA zeolite membrane layer, resulting in an unprecedented hierarchical membrane structure. Specifically, the hierarchical LTA zeolite membranes composed of a macroporous zeolite layer and a thin dense top layer (600 nm), are fabricated on rough α -Al 2 O 3 tubular supports by vapor phase transformation method using mesoporous silica spheres (MSPs) as the porogen in the precursor layer. The H 2 (N 2) permeance of the hierarchical LTA zeolite membrane is near 10 times that of the conventional LTA zeolite membrane, indicating that the hierarchical pore structure can effectively weaken the mass transfer resistance inside the selective layer of membrane. And it has good pervaporation performance for 90 wt% ethanol aqueous solution at 348 K, i.e. , the flux can reach 4.54 kg m−2 h−1 with a separation factor of >10,000, which is much higher than that of the conventional LTA zeolite membrane. The preparation of LTA zeolite membranes with hierarchical pore structure using MSPs as a porogen is expected to open up a new way for the construction of zeolite membranes. • Mesoporous silica microspheres as the porogen and silica source. • Hierarchical membrane structure can effectively decrease the permeation resistance. • Solid waste was greatly reduced by vapor phase transformation process. [ABSTRACT FROM AUTHOR]

Zeolite membranes are broadly applied in separation, catalysis, and sensor, yet challenges remain in the preparation process. The design of support is an important component to simplify the synthesis protocol and improve the repeatability. Herein, we present a facile and universal strategy to fabricate high-performance zeolite membranes via engineering the skeleton of hollow fiber supports, on which a variety of high-performance zeolite membranes (e.g., MFI, LTA and FAU) can be obtained just by in-situ crystallization without any modification. The "reactive" support is fabricated by implanting zeolite crystals (e.g., NaA) in the precursor of porous ceramic alumina support. Being dissolved under alkaline condition of the synthesis solution, the zeolite calcination transformant (e.g., NaA-Cal) produced in the support during sintering process can effectively form nucleation sites on the support surface, and continuously provide active species to ensure the continuity of the membrane. This study contributes new insights into the importance of supports for high-performance zeolite membranes. Meanwhile, the synthetic methodology is expected to expand the preparation method of zeolite membranes and promote the large-scale application of zeolite membranes. [Display omitted] • Implanting zeolite crystals into the ceramic slurry for preparation of versatile supports. • A variety of high-performance zeolite membranes can be obtained on the support. • No modification or repeated synthesis is needed using the versatile support. [ABSTRACT FROM AUTHOR]