(229b) Mesoporous ?-Al2O3 Supported Amine-Based Fiber Sorbents for Direct Air Capture of Carbon Dioxide

Direct air capture (DAC) involving direct removal of CO₂ from ambient air has emerged as a promising “negative emissions” technology that can counterbalance carbon emissions that cannot be eliminated at the source. Amine-functionalized porous materials such as zeolites, mesoporous silica, mesoporous alumina (Al₂O₃), and metal-organic frameworks (MOFs) comprise the dominant class of solid adsorbent materials studied for DAC. Fiber sorbents are hybrid materials made of solid sorbent particles dispersed in macroporous polymer matrices with fiber geometries comparable to mixed matrix membranes. They can be fabricated as scalable forms of these DAC sorbents, providing high surface area-to-volume ratios, high packing densities, high sorbent loadings, low pressure drop, and enhanced CO₂ adsorption kinetics. Mesoporous silica, zeolite and MOF-based fiber sorbents have been previously reported in literature, for post-combustion CO₂ capture and DAC. While amine-loaded mesoporous γ-Al₂O₃ sorbents have been extensively studied for DAC, their potential to be fabricated as fiber sorbents for DAC has not been investigated yet.

To this end, the focus of this presentation will be on novel amine-loaded γ-Al₂O₃ fiber sorbents for DAC. γ-Al₂O₃/polymer composite fibers were easily fabricated using the dry-jet/wet-quench fiber spinning process, which follows non-solvent induced phase separation (NIPS) of sorbent-dispersed polymeric solutions. Amine-loaded γ-Al₂O₃ fiber sorbents were obtained by impregnating polyethyleneimine (PEI) into the mesopores of γ-Al₂O₃ dispersed in the γ-Al₂O₃/polymer composite fiber. DAC performance of the fiber sorbents under multiple CO₂ adsorption/desorption cycles will be reported to demonstrate their long-term stability under continuous operation. With the added advantage of scalability, amine-loaded γ-Al₂O₃ fiber sorbents can provide a valuable and versatile platform for implementation as structured DAC sorbent contactors on the commercial scale.