(626d) Ultrathin Zeolite Nanosheet/Polymer Composite Membranes for Gas Separations

Membrane-based separation processes offer a compelling energy-efficient alternative to traditional phase-change driven separations. Among the most promising candidates for next-generation membranes are two-dimensional (2D) zeolites, which combine the high selectivity and stability of crystalline frameworks with the processability of nanosheet morphologies. However, scalable fabrication of defect-free zeolite nanosheet laminated membranes remains a persistent challenge due to structural imperfection for the nanosheets, such as branching or thicker sections, and additional crystal growth step to eliminate the defects. This work addresses these limitations through a novel approach that recovers monolayer zeolite nanosheets (MZNs) with uniform thickness. Such nanosheets are ideal for ultrathin nanosheet laminated film coating with minimal defects. Additionally, a new methodology is introduced to fabricate nanosheet/polymer composite membranes, in which the zeolite loading is very high that molecules primarily transport through the zeolite phases. The membranes are anticipated to achieve zeolite membrane-like performance without the necessity of hydrothermal synthesis. The straightforward methodology also enables scalable membrane fabrication. The membrane separation performance is rigorously evaluated using both single gases and gas mixtures to assess the membranes' suitability for industrial applications. Characterization is conducted to understand the microstructure of the membranes and its influence on membrane separation performance. This research represents a step forward in achieving 2D crystalline materials with minimal structural imperfection and paves the way towards practical membrane applications.