Chemical Modification of Polymer-Based Membranes for Carbon Dioxide Gas Separations

The effects of climate change are becoming more drastic as carbon dioxide continues to be released into the atmosphere. Reductions in industrial emissions along with the use of direct air capture technology are necessary to prevent further atmospheric warming. PEG-based polymer membranes present a potential solution for carbon dioxide separation as they are energy efficient, relatively inexpensive, and easy to synthesize and alter. Lewis bases are substituted onto ligands on the network’s scaffolding through “click chemistry”. These basic groups interact with carbon dioxide to promote facilitated transport, a process by which a gas is selectively passed through the membrane.

This study aims to push the boundaries of permeability and selectivity of CO₂ gas in polymer membranes by testing membranes with ligands of varying basicity, and thus varying strength of interactions with carbon dioxide. We hypothesize that stronger interactions with CO₂ would generally promote higher selectivity. However, if the interactions are binding, CO₂ may become trapped in the membrane and hinder selective diffusion. Future plans include characterizing the structure and transport properties of hydrated PEG-based membranes using sorption, dilation, and humidified gas permeation testing.

J. D. Moon et al. Macromolecules 2021, 54, 2, 866–873.

Tong, Zi Journal of Membrane Science 2017, 543, 202–11.

J. D. Moon et al. Journal of Membrane Science 2021, 639, 7197-7208