(401j) The Impact of PEO-Ionic Liquid Synergy in PEBAX®/[EMIM[Tf?N] Membranes in CO2 Capture

The mitigation of greenhouse gas emissions, particularly CO₂, is a paramount engineering challenge, necessitating the development of advanced, energy-efficient separation technologies. This study investigates the impact of embedding the ionic liquid (IL) [EMIM][Tf₂N] within various grades of PEBAX^® poly(ether-block-amide) on the CO₂ sorption rates and gas transport characteristics of Supported Ionic Liquid Membranes (SILMs). We examine how the compositional blend of the hard polyamide (PA) and soft polyether (PEO) blocks in PEBAX^® influences CO₂/N₂ separation efficiency, hypothesizing that higher PEO content leads to enhanced CO₂ sorption and selectivity due to more effective interactions between PEO and IL.[1] We explore four distinct grades of PEBAX^®, 1657, 1074, 2533, and RNEW, each featuring different PA/PEO ratios, to determine their impact on CO₂ capture performance. Our experimental results demonstrate that membranes with higher PEO content, particularly PEBAX^® 2533 and RNEW (approximately 80% PEO), achieve significantly higher CO₂ uptake and superior CO₂/N₂ selectivity. For instance, PEBAX^® 2533 and RNEW exhibit enhanced CO₂ sorption capacity (up to ~3.0 mmol CO₂ per kg IL under 10 °C and 200 psi) and improved CO₂ permeability (up to 618 Barrer) and CO₂/N₂ selectivity (up to 55), compared to those with lower PEO content. Utilizing a suite of characterization techniques, such as FTIR, DSC, XRD, SEM, and gas permeation tests, we investigate the structural and performance aspects of these membranes. Our findings reveal that PEBAX^® membranes enriched in PEO, when integrated with [EMIM][Tf₂N], not only promote increased CO₂ sorption but also substantially enhance gas separation efficiency. This study highlights the potential of PEO-rich PEBAX^®/[EMIM][Tf₂N] membranes for effective CO₂ capture and contributing to sustainable efforts in greenhouse gas mitigation. The results suggest that the strategic incorporation of IL into PEO-rich segments facilitates superior CO₂ transport properties, making these membranes promising candidates for next-generation carbon capture technologies.