Dual Layer Spinning with Lumen Layer Containing PAI/Silica/PEI Hollow Fiber Sorbent for CO2 Separation by Rapid Temperature Swing Adsorption

Amine-loaded cellulose acetate (CA) polymer/silica hollow fiber sorbents for post-combustion CO₂ recovery were fabricated by utilizing a post-spinning amine infusion technique. Building on prior work focusing on amine-loaded CA and poly(amide-imide) (PAI)/silica hollow fiber sorbents, direct dual layer spinning with PAI lumen layer PAI/silica/ poly(ethyleneimine) (PEI) hollow fiber sorbent are reported here for the first time. Post-spinning amine infusion of PEI is used to incorporate amine sites during the solvent exchange steps after dual layer fiber spinning.  After infusing the 50 wt% silica hollow fiber sorbents with 10% PEI solutions in methanol, several amine-loaded fibers were assembled into shell-and-tube modules and exposed on the shell side at 1 atm and 65 °C to simulated flue gas with an inert tracer (14 mol% CO₂, 72 mol% N₂ and 14 mol% He at 100% R.H.).  The fibers are found to have a humid breakthrough CO₂ capacity of 1.0 mmol/g-fiber sorbent. The humid CO₂ pseudo-equilibrium uptake of the module is 3.0 mmol/g-fiber sorbent. This approach provides a versatile platform that may facilitate the ultimate scale-up of practical amine sorbents for flue gas CO₂ recovery applications.