Application of Amine-Tethered Solid Sorbents for Direct CO2 Capture from the Ambient Air

While current carbon capture and sequestration (CCS) technologies for large point sources can help address the impact of CO2 buildup on global climate change, these technologies can at best slow the rate of increase of the atmospheric CO2 concentration. In contrast, the direct CO2 capture from ambient air offers the potential to be a truly carbon negative technology. We propose here that amine-based solid adsorbents have significant promise as key components of a hypothetical air capture process. Specifically, the CO2 capture characteristics of hyperbranched aminosilica (HAS) materials are evaluated here using CO2 mixtures that simulate ambient atmospheric concentrations (400 ppm CO2 = "air capture") as well as more traditional conditions simulating flue gas (10% CO2). The air capture experiments demonstrate that the adsorption capacity of HAS adsorbents are only marginally influenced even with a significant dilution of the CO2 concentration by a factor of 250, while capturing CO2 reversibly without significant degradation of performance in multicyclic operation. These results suggest that solid amine-based air capture processes, have the potential to be an effective approach to extracting CO2 from the ambient air.