Enhancing the CO2 Separation Performance of Mixed Matrix Membranes Based on Block Copolymer via Nonsolvent-Induced Microstructure Rearrangement

Abstract

To strengthen the competitiveness of membrane-based CO₂ capture technology, developing membranes with high CO₂ separation performance is crucial. In this study, mixed matrix membranes (MMMs) were prepared by incorporating various concentrations of fumed silica (FS) into block copolymers (i.e., Pebax and SBS). The results showed that the CO₂ permeability of both Pebax and SBS initially increased before decreasing as FS loading increased. Next, the MMMs were immersed in deionized (DI) water at room temperature (RT) to induce microstructural rearrangement. Results indicated that with an FS loading of 1 wt %, the CO₂ permeability of Pebax-FS 1 wt %-Water membranes increased to 757.4 Barrer, 1.6 times higher than that of MMMs with the same FS concentration (477.8 Barrer). Likewise, the CO₂ permeability of the SBS-FS 1 wt %-Water membranes increased to 385.2 Barrer. These findings suggest that the nonsolvent-induced microstructural rearrangement technique is simple, environmentally friendly, and has the potential to significantly improve the CO₂ separation performance of MMMs based on different block copolymers.