(520g) Post Spinning Modification of Porous Organic Cage Fiber Sorbents for CO2 Capture

It is clear that CO₂ capture from point sources and direct capture from ambient air is necessary to achieve global climate goals and avoid excessive global temperature increases. One method to develop effective adsorbents for CO₂ is to impregnate mesoporous or microporous materials with polyamines like branched polyethylenimine (PEI) or tetraethylenepentamine (TEPA). Here a new class microporous materials, porous organic cage (POCs) are explored as a base material for PEI impregnation. CC3 is the POC used in this work and it has been previously spun into polymeric fiber sorbents for adsorptive separation applications. CC3 is composed of chemically weak imine bonds which should be vulnerable to degradation from primary amines present in PEI. Unexpectedly, CC3 maintains its microporosity and chemical structure after extended PEI exposure. The CC3-PEI fibers are characterized via TGA, SEM, FTIR, N₂ physisorption at 77K, and CO₂ isotherms. CC3 fibers impregnated with PEI consistently showed higher CO₂ uptakes at low pressures showing that PEI was contributing to CO₂ capture along with CC3. Breakthrough studies were conducted with these CC3-PEI fibers and compared to mesoporous silica-PEI fibers to compare the kinetics of CO₂ uptake. This work shows that imine based POCs can be combined with PEI to make them effective adsorbents for CO₂ capture.