Directly Spun Epoxy‐Crosslinked Polyethylenimine Fiber Sorbents for Direct Air Capture and Postcombustion Capture of CO2

A novel, directly‐injected solid fiber sorbent is synthesized from a solvent‐stable, epoxy‐crosslinked basic immobilized amine sorbent (BIAS) for CO 2 capture. Leach resistance of the BIAS organics toward 1‐methyl‐2‐pyrrolidone/H 2 O (90/10, fiber solvent) reaches near 100% at the expense of CO 2 capture and is achieved by increasing the extent of crosslinking. The optimized fiber sorbent, prepared with an N,N‐diglycidyl‐4‐glycidyloxyaniline/polyethylenimine (PEI)‐0.35/1 wt. ratio, retains 79.2% of PEI and captures 0.37 (direct air capture [DAC]) and 0.67 (postcombustion) mmol CO 2 g‐fiber −1 . A nonoptimized prototype hollow fiber exhibits a stable 0.2 mmol CO 2 g‐fiber −1 during DAC cycling and is assembled into a ten‐fiber module. These results demonstrate a large step toward practical application of this material.