(589h) Carbon Dioxide Diffusivity Measurements in Support Materials Using the Zero Length Column Method in Breakthrough Adsorption

Carbon dioxide has been extensively studied due to increasing concerns regarding global warming and its rising concentration in the atmosphere. Capturing carbon dioxide from flue gas streams and the atmosphere is critical to reverse the trend and lessen the environmental impacts of global warming. Solid adsorbents have gained increasing attention due to their low regeneration costs compared to liquid amine sorbents, however, few studies have investigated the kinetics of adsorption.

In this work, zeolite 5A, zeolite 13X, and mesoporous silica-alumina were analyzed using the zero-length column method for carbon dioxide adsorption. The zero-length column method involves loading a small quantity of material into a breakthrough column, saturating the sample, and then monitoring the effluent concentration after switching back to an inert gas flow. The desorption profile shows slow desorption of carbon dioxide from the sample without the aid of heat. From this desorption profile, the diffusivity of carbon dioxide in the pores of the adsorbent materials was determined. Zeolite 5A and zeolite 13X displayed similar diffusivities while silica-alumina showed a roughly 60% increase in carbon dioxide diffusivity compared to the zeolites. This test was repeated at several inert gas flowrates, showing the independence of flowrate on the calculated diffusivity. This work provides a baseline for further studies into the kinetics of carbon capture. Understanding the kinetics of carbon capture is critical for developing better materials to offset the effects of global warming.