Highly selective thin B-oriented MFI zeolite membranes on scalable modified stainless steel supports

Enhancing the separation performance of molecular sieve membranes relies significantly on precise control over their membrane morphology and microstructure. This involves creating thin, closely packed, oriented, and uniform coatings of seed crystals, enabling subsequent intergrowth to establish continuous membranes. To address industrial needs, it is crucial to generate a thin and flawless membrane efficiently producible on a large-scale support. Porous stainless supports offer scalability and easy integration into membrane modules. In this study, we present a novel and straightforward process for modifying stainless-steel supports to seed zeolite membrane layers. High-performance, b-oriented MFI zeolite membranes can be synthesized on these modified stainless-steel supports through scalable filtration seeding of MFI zeolite nanosheets followed by secondary growth. By employing a carefully designed pre-treatment procedure, we achieved the growth of well-intergrown, highly b-oriented MFI zeolite membranes on the modified stainless-steel support, establishing a robust interaction with the substrate. The membranes, fabricated through gel-free secondary growth of nanosheets deposited on a scalable stainless-steel support using this technique, demonstrate ultra-selective capabilities in separating para-xylene from ortho-xylene, with a high separation factor of 388.