Support-Layer Integrated Zeolite Membranes through In Situ Interfacial Transformation of Clay-Based Protomembranes

Zeolite membranes are considered ideal inorganic membrane materials for separating mixtures with molecular-level differences. However, their complex preparation process with excessive synthesis solutions for traditional hydrothermal heating methods leads to various drawbacks. Here, we describe a membrane preparation strategy involving an in situ interfacial transformation of the protomembrane without solvents. Inexpensive clay powder forms the protomembrane, and the active ingredients subsequently migrate from the interior of this protomembrane to its surface and transform into a zeolite layer. Ultimately, the protomembrane is calcined to obtain the support-layer integrated zeolite membrane. Systematic research shows that clay not only serves as a raw material for the support but also provides active ingredients for the growth of zeolite crystals; thus, zeolite membranes with zeolite particles inserted into the support are formed. The zeolite membrane calcined at 800 °C possesses a p-xylene/o-xylene separation factor approaching 6263 with a permeation flux of 1.21×10^-7 mol ⋅  m^-2 ⋅  s^-1 ⋅  Pa^-1. This interfacial transformation method can be applied to other membranes and promote the development of membrane separation technology.