(425f) Development of Polyamide-Coated Adsorbents Via Vapor Phase Interfacial Reaction for 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, polyamide coatings generated on the surface of mesoporous silica via vapor phase interfacial reaction were used to seal small amines inside the pores of the silica in order to enhance thermal stability without compromising CO₂ uptake capacity. The polyamide coating 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 31 simulated adsorption-desorption cycles, a polyamide-coated adsorbent achieved an capacity of 2.67 mmol CO₂/g and a loss of 6.9% in dry DAC conditions.