(43h) A Thin Film Approach to Rapid, Quantitative Characterization of Competitive CO2/Water Adsorption in a Sorbent Material

Measuring mixed-gas adsorption is a significant challenge across many industries including commercial gas separations and carbon capture. Existing measurement techniques are material-intensive, slow, low-throughput, and can be difficult to access.¹ To address this, we have developed specialized instrumentation capable of fast and accurate measurements of competitive adsorption of polar/nonpolar binary gas mixtures. Our instrument measures sorbents in the form of thin films on mass and capacitance transducer devices. The thin film form factor requires very little sorbent (~micrograms), and the compact device architecture allows scalability for high throughput screening. Our thin film casting process has shown a high rate of success across sorbent types when particle size is limited to ~10μm.

We show quantitative measurements of CO₂/water binary uptake in CALF-20² (a MOF material used for carbon capture) across a range of temperatures, demonstrating the ease and speed of this measurement method. Our mixed-gas isotherms of CALF-20 agree with those previously published.² Additionally, our isotherm measurement technique is relatively fast (40-120 min per data point). Because of this, we are able to report the first mixed-gas isotherms on CALF-20 at three different temperatures. We show that increasing the adsorption temperature for a particular gas composition leads to an increase of CO₂ uptake relative to water uptake. Our thin film measurement technique quickly provides novel information that could significantly accelerate sorbent development for carbon capture and, in the future, other sorption fields and applications.

References

1. Shade, D.; Bout, B. W. S.; Sholl, D. S.; Walton, K. S. Opening the Toolbox: 18 Experimental Techniques for Measurement of Mixed Gas Adsorption. Eng. Chem. Res. 2022, 61 (6), 2367-2391.

2. Lin, J. B.; Nguyen, T. T. T.; Vaidhyanathan, R.; Burner, J.; Taylor, J. M.; Durekova, H.; Akhtar, F.; Mah, R. K.; Ghaffari-Nik, O.; Marx, S.; Fylstra, N.; Iremonger, S. S.; Dawson, K. W.; Sarkar, P.; Hovington, P.; Rajendran, A.; Woo, T. K.; Shimizu, G. K. H. A scalable metal-organic framework as a durable physisorbent for carbon dioxide capture. Science 2021, 374 (6574), 1464-1469.