(152bj) Multi-Ligand Hybrid Approach to Tailoring Zeolite Imidazolate Frameworks for Highly CO2-Selective Mixed Matrix Membranes

Polymeric membranes incorporated with dispersed nanofillers, called mixed matrix membranes (MMMs), are considered to be the next-generation gas separation membranes owing to their excellent separation performance. In this presentation, I will discuss a multi-ligand hybrid approach to fabricating highly CO₂-selective zeolitic imidazolate framework (ZIF) nanofillers. Our newly developed ZIF nanofillers, called a triple ligand, amine modulated ZIF-8 (TAZIF-8), were made by coordinating zinc metal ions with three different organic ligands, including 2-methylimidazole (Mim), tributylamine (TBA), and 3-amino-1,2,4-triazole (Atz) via post-synthetic modification. The Zn-Mim coordination contributes to retain an open porous sodalite topology, while the Zn-TBA analog provides high processability. Lastly, the Zn-Atz coordination enables CO₂-selective permeation through a combination of enhanced size discrimination and specific interactions. A flat sheet 6FDA-DAM/TAZIF-8 (40 wt%) MMM exhibits an almost threefold increase in CO₂ permeability and a twofold increase in CO₂ selectivity over other light gases (N₂, CO, or CH₄) compared to the 6FDA-DAM membrane [1]. In addition, I will discuss a scalable fabrication method for defect-free TAZIF-8 mixed matrix hollow fiber membranes (MMHFMs) using a dip coating process. The effect of different process variables on the structure and separation performance of the resulting MMHFMs is investigated with the analysis of the dual-stage CO₂ capture process using different MMHFMs.

ACKNOWLEDGMENTS

This research was supported by the C1 Gas Refinery Program through the National Research Foundation of Kore (NRF) funded by the Ministry of Science and ICT (Project No. 2019M3D3A1A01069101) and supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (Project No. RS-2023-00214333).