Trio-Modulated Strategy in γ-Cyclodextrin-Modified Polyamide Membranes for Enhanced CO₂Separation

Membrane separation technology has great potential for application in gas separation due to its environmentally friendly, efficient, and energy-saving advantages. Polyamide (PA) membrane is an ideal material for efficient separation of CO₂ due to its high amine density and excellent CO₂ affinity. This work presents a trio-modulated strategy that enhances the CO₂ separation performance of PA membranes by modifying the substrate, optimizing the preparation method, and incorporating fillers. Substrate modification facilitates the interfacial polymerization of a polyamide layer on a polysulfone substrate. PA membranes fabricated via vapor–liquid interfacial polymerization typically exhibit a low defect density and superior CO₂ separation performance. The incorporation of fillers (γ-cyclodextrin, namely γ-CD) can effectively loosen the microstructure of the PA membrane, and the CO₂-philic groups of γ-CD fillers furtherly enhance the selectivity of CO₂ through the facilitated transport mechanism. The prepared membranes display excellent CO₂ separation performance with CO₂/N₂ selectivity of 479.5, CO₂/CH₄ selectivity of 395.9, as well as a CO₂ permeance of 4179.8 GPU. The proposed strategy provides a facile and effective route to trio-modulated PA membranes for the study of CO₂ separation and can provide a avenue for the development of advanced membrane materials for CO₂ separation.