(452c) New Poly(alkyl imines) for CO2 Capture from Ambient Air

Research efforts in CO₂ capture technologies have dramatically increased due to interest in reducing the effect of anthropogenic emissions on atmospheric CO₂ concentrations. Much of this research has focused on capture from large point sources such as flue gas. Direct capture of CO₂ from ambient air is proposed as a complementary technology that has the advantage of not needing a flue gas feed stream and thus is more versatile in its deployment. However, at an ultradilute concentration of 400 ppm, the driving force for adsorption is low, necessitating the development of adsorbents that may be different from those used in flue gas capture. Additionally, these adsorbents must be stable under oxidizing conditions due to the presence of oxygen in the feed stream.

In this work, we present work towards the development of a series of new poly(alkyl imines) as well-defined branched molecules for CO₂ capture. By changing the structure and flexibility of the adsorbent aminopolymer, we show that the CO₂ capture capacity and efficiency can be readily tuned. These materials represent a departure from the traditionally-studied poly(ethylenimine) (PEI) for CO₂ capture by using a well-defined molecular species with controlled and varied alkyl linker length. Additionally, these structures only contain primary and tertiary amines, which impart high capture capacity under ultradilute conditions and stability against oxidative degradation.