(739g) Synthesis of Water-Sensitive Metal-Organic Frameworks within Fiber Sorbent Modules

Metal-Organic Frameworks have garnered significant attention as sorbent materials for a wide variety of industrial gas separations. A potential vehicle for their application is the incorporation of MOFs into fiber sorbent contactors, in which high loadings of sorbent are dispersed within a porous polymer matrix. Due to the structured nature of these contactors, pressure drops across modules are significantly reduced and lend themselves to more rapid pressure and temperature swing cycles. However, fiber sorbents are produced via polymer solution phase inversion techniques and expose the sorbents to water, solvents, and sonication, and therefore is limited to the use of highly stable sorbents. A large portion of MOFs, including those with the highest performance in CO₂ capture, are at least somewhat unstable in humid and aqueous conditions, making them difficult to incorporate without catastrophic loss of porosity. If MOF sorbents were incorporated into the fibers after the spinning process, their degradation under spinning conditions could be circumvented.

In this talk, we present a synthesis route for the production of water-sensitive MOFs in polymer fiber sorbents by the use of metal oxides as sacrificial seeds. Cellulose acetate/ZnO (48 wt %) fibers were spun using a dry-jet wet-quench method and converted into HKUST-1 and ZIF-8 through hydroxy double salt (HDS) intermediates in a post-spinning process. Final MOF loadings within the polymer sorbent reached 85 and 66 wt % respectively as determined by N₂ physisorption. We further demonstrate this process on module-packaged CA/ZnO fibers, in which ready-to-use fiber sorbents are produced in a moisture free environment and with minimal handling. These modules are then employed in proof-of-concept CO₂/N₂ breakthrough experiments.