Biomimetic Insights into ZIF-8-CO2 Interactions: Elucidating Capture Dynamics through Comparison with Carbonic Anhydrase and In Situ DRIFTS

This study investigates the CO2 capture dynamics of the metal-organic framework ZIF-8, drawing biomimetic inspiration from its structural similarity to the enzyme carbonic anhydrase. By evaluating ZIF-8 in a CO2-saturated aqueous medium via pH-monitoring electrometric assays, distinct behaviors were observed. While the free enzyme rapidly accelerates CO2 hydration, ZIF-8 demonstrates a concentration-dependent buffering effect, stabilizing the solution's pH at higher levels. This indicates that ZIF-8 interacts with dissolved CO2 prior to or concomitant with its hydration. Furthermore, in situ DRIFTS measurements and BET characterization confirm that direct molecular adsorption within the porous framework, combined with the intrinsic acid-base properties of ZIF-8, governs its macroscopic response. These findings provide valuable insights into the physicochemical mechanisms driving ZIF-8 in carbon capture systems.