Surface-Modified Sodalite (SOD) Zeolite and Preparation of Mixed Matrix Membranes with Polymers of Intrinsic Microporosity (PIM-1) for Efficient Gas Separation

Zeolite is a commonly utilized filler in mixed matrix membranes (MMMs) to enhance the effectiveness of gas separation due to its molecular sieving properties with high separation coefficients. However, the compatibility and suitability between the zeolite and the polymer membrane are prerequisites for preparing homogeneous membranes and an essential factor affecting gas separation performance. Herein, we synthesized nucleus-crown-crown structures by surface modification of SOD zeolite and prepared MMMs by doping them into Polymers of Intrinsic Microporosity (PIM-1) for efficient gas separation. FTIR, XRD, SEM, and TGA characterized the fillers and the MMMs. The average particle size of the filler was estimated to be approximately 552.43 nm by SEM images. The surface-modified SOD zeolite facilitates the rapid permeation of specific gas molecules and enhances the dispersion of SOD zeolite in the PIM-1 membrane, thereby improving gas separation performance. Compared with pure PIM-1 membrane, the MMMs with a loading of 7 wt % exhibited CO2 and H-2 permeabilities reaching up to 7000.0 and 3600.0 Barrer; their selectivities for CO2/N-2 and H-2/N(2 )were measured at 17.7 and 9.29, respectively. MMMs with the best fill ratios exceeded the 2008 Robeson upper limits. The methods for surface modification of SOD zeolites provide a new way for the application of SOD zeolite in the area of gas separation.