(494f) Exploring Direct Air Capture at Cold Temperatures

Removal of CO₂ directly from the air is recognized as one of the potential solutions for climate change. Adsorption-based direct air capture (DAC) approaches are emerging as a scalable and potentially low-cost DAC method. However, so far, almost all studies on DAC have been conducted at temperatures 25 °C. Given that most of the areas in the world show annual temperatures lower than 25 °C and some regions exhibit a large diurnal temperature difference in a day, it is desirable to explore the CO₂ sorption behavior of materials not only at ambient (25 °C) but also sub-ambient conditions. In addition, these cold temperatures offer advantages for DAC such as higher gas adsorption capacity and lower absolute humidity. Considering this, we have evaluated zeolites and amine-functionalized MIL-101(Cr) for cold temperature DAC deployment. In this presentation, low silicon-to-aluminum ratio zeolites will be discussed as a class of physisorbents for economic cold DAC operation and compared with amine-functionalized MIL-101(Cr). Amine-functionalized MIL-101(Cr) fibers were evaluated at cold temperatures using rapid temperature vacuum swing adsorption (RTVSA). The talk will discuss the potential of DAC in cold environments with suggestions about sorbent design for cold-temperature DAC.