Publications

Removing carbon dioxide from gas streams is important for reducing human-caused emissions. Membrane-based CO₂ capture is attractive because it can be compact, scalable, and easily adjusted. In this work, we built a small experimental system that mimics the operation of a multi-stage membrane module, allowing us to study CO₂ capture step by step under different gas compositions.

We found that oxygen in the feed gas strongly affects the concentration of CO₂. Lowering the oxygen content greatly reduces the number of membrane stages needed to reach CO₂ levels suitable for further use, especially when starting from dilute CO₂ streams. This effect is smaller when the gas already contains a lot of CO₂. Our experiments and simulations show that oxygen cannot be ignored in the design of membrane CO₂ capture systems. Considering CO₂/O₂ separation and removing oxygen before capture could make it easier to use simple, low-cost membranes for capturing CO₂ from dilute sources.