(371h) Enabling Upgradation of Captured Carbon Dioxide with Carbon Molecular Sieve Membranes

This work focuses on the electrochemical conversion of captured CO₂ into C₂H₄, which is a high value product widely used across chemical and polymer industries. However, the product stream from this process is not pure: it contains unreacted CO₂, CO as an impurity and C₂H₄ as the desired product. Membranes-based separation offers a promising route to selectively remove CO₂ and CO while purifying C₂H₄. CO₂ (T_C = 304K) (0.330nm) and C₂H₄ (T_C = 282K) (0.375nm) are both condensable gases but the size difference between them could be leveraged for this separation. In contrast, CO (T_c = 133K) (0.376nm) and C₂H₄ are identical size, making their separation challenging based on size alone, but differences in condensability open up another path for their separation. In this presentation, I will describe the methods to evaluate the thermodynamic and kinetic parameters of polyimide-derived carbon molecular sieve (CMS) membranes that govern the transport of CO₂, C₂H₄ and CO. Using temperature-dependent permeation and sorption measurements, we extract intrinsic transport parameters such as activation energies, heat of sorption, which are critical to predict the transport in CMS. I will also highlight how different gases interact with the distinct transport and sorption domains within the CMS structure, and what that tells us about designing membranes for captured carbon utilization. This talk aims to provide a material-based framework for advancing membrane separations in carbon utilization.