(442f) Scalable Materials Solutions for the Deployment of Adsorption-Based Direct Air Capture Technologies

The anthropogenic removal of CO₂ from ambient air using direct air capture (DAC) technology is receiving increasing attention recently in light of the need for negative emissions technologies that reverse current trends in atmospheric CO₂ concentrations. Capture materials considered thus far for the most part comprise organic components in addition to inorganic ones, with the former resulting in inherent limitations in hydrothermal and oxidative stability. I discuss here how materials that are purely inorganic in composition can capture CO₂ reversibly under ambient conditions in the presence of humidity, thereby significantly simplifying process complexity and cost. Unlike most inorganic sorbents that are either intolerant to water or require regeneration temperatures in excess of 300°C, mixed metal hydroxides can capture and release CO₂ with a less than 100°C swing in temperature. They are also exceedingly hydrothermally and oxidative stable, as reflected in cycling experiments with steam and oxygen. This talk will discuss how this novel class of DAC sorbents circumvents challenges relating to material precursor availability, cost, and stability. Potential contactor designs for scaling up DAC will also be discussed.