(703d) Entrapment of Small Amines in Mesoporous Silica Via Polymeric Coating for the Direct Air Capture of CO2

Since the industrial revolution, the concentration of CO₂ in the atmosphere has been continuously rising, resulting in considerable increase in earth temperature. Due to continuous increase in CO₂ emissions, the target of restricting “global warming to 1.5^oC” by the Intergovernmental Panel on Climate Change (IPCC) can only be met by negative CO₂ emissions techniques, such as the direct air capture (DAC) of CO₂. Therefore, significant research has been focused on capturing CO₂ from air. Most of the researchers have focused on polymeric amine-based sorbents to ensure thermal stability during temperature swing adsorption. However, it compromises the efficiency of the sorbent material and thus CO₂ uptake capacity. A significant amount of research has been focused on countering this challenge of tradeoff between the thermal stability and CO₂ capacity of sorbent materials. In this work, polymeric coatings were used to seal small amines in a mesoporous silica in order to enhance the thermal stability without compromising CO₂ uptake capacity. Different polymeric coatings, including polyamide and Pebax, were used, which allows for CO₂ diffusion without significant resistance through the coating material during adsorption-desorption steps but prohibits leakage of amines, ensuring long-term thermal stability of the sorbent material. For 10 adsorption-desorption cycles, CO₂ capacity loss was reduced from 6.9% for the base sorbent without a coating to negligible loss for the polyamide coated sorbent.