(508b) Polymer-Sorbent Direct Air Capture Contactors with Engineered Geometries Via Templated Phase Inversion

Developing low-cost direct air capture (DAC) systems requires gas–solid contactors that have efficient heat and mass transfer while minimizing pressure drops. Triply periodic minimal surfaces (TPMS) offer superior mass and heat transport properties compared to conventional geometries; however, fabricating TPMS-shaped contactors using traditional methods such as injection molding remains challenging. Non-solvent-induced phase separation (NIPS) of polymeric inks embedded with adsorbents has been explored as a method for producing contactors with efficient mass transport properties, but prior implementations have been mostly limited to simple geometries like films and fibers.

This study presents a templated phase inversion (TPI) technique, where NIPS takes place within a simultaneously-dissolving, water-soluble, 3D-printed template, enabling the fabrication of complex macroscopic architectures, including TPMS contactors. This flexible approach supports a wide range of adsorbents, including zeolites, silica, activated carbon, and metal–organic frameworks. Structural and morphological analyses using scanning electron microscopy (SEM), micro-computed tomography, and nitrogen adsorption experiments reveal the hierarchical porosity and geometric precision of the resulting sorbent contactors. TPMS DAC contactors incorporating poly(ethyleneimine)/silica adsorbents demonstrate CO₂ capture performances that rival or surpass those of other contactor geometries.