(633f) Effect of Amine Structure On CO2 Adsorption From Ultra-Dilute Gas Streams Such As Ambient Air

The direct extraction of CO₂ from the ambient atmosphere, or “air capture,” has the potential to reduce the global atmospheric CO₂ concentration if applied on a massive scale, as it can account for all sources of CO₂ emissions, as opposed to flue gas capture which only captures emissions from a singular point source. In the long term, if economically feasible, this technology has the potential to impact the climate change associated with anthropogenic CO₂ emissions. It has previously been demonstrated in our group that amine oxide hybrid materials are effective adsorbents for extraction of CO₂ from simulated ambient air.  For example, silica supported hyperbranched aminosilicas (HAS) were demonstrated to capture CO₂ from a 400 ppm gas stream with as little as a 2.2 factor decrease in capacity as compared to conditions simulating flue gas capture (10% CO₂ stream). Thus a very moderate 2-10 decrease in capacity can be easily observed with a significant, 250 fold decrease in inlet CO₂ concentration. Subsequently, PEI-impregnated silica materials were shown to give exceptionally high adsorption capacities under air capture conditions.  In this work, the effects of amine structure on both CO₂ and water adsorption have been studied as they are the two key adsorbing components in air. The results of these studies allow for rational design of optimized, next generation adsorbents for CO₂ extraction from ultra-dilute gas streams such as ambient air.