MUF-16: A Robust Metal-Organic Framework for Pre- and Post-Combustion Carbon Dioxide Capture

Abstract

One of the most critical environmental issues of our age is the escalating release of CO₂ into the atmosphere. Separation technologies with low energy footprints may be an effective way to capture CO₂ and prevent its accumulation. Metal-organic frameworks (MOFs) can meet separation challenges due to their tailored structures and tunable pore surfaces. However, obstacles to their deployment can include the energy consumed by regeneration, a lack of long-term structural stability, and their production on large scales. Herein, we report on MUF-16 ([Co(Haip)₂], H₂aip = 5-aminoisophthalic acid), a hydrogen-bonded water-stable microporous material that combines high CO₂ adsorption with a low affinity for other gases. MUF-16 is built up from inexpensive starting reagents in a scalable process. It can be easily regenerated at room temperature by purging with inert gas, and it maintains its performance over multiple adsorption/desorption cycles. MUF-16 features one-dimensional channels that trap CO₂ guest molecules by a raft of attractive electrostatic interactions and size complementarity. It rejects H₂ and N₂ molecules around room temperature. This was verified by simulated and experimental breakthrough separation measurements on CO₂/N₂ and CO₂/H₂ mixtures. MUF-16 can be pelletized by coating with polymeric poly(vinylidene difluoride) (PVDF) to render it compatible with large-scale applications.

Keywords: adsorption; gas separation; metal-organic-framework; post-combustion carbon capture; pre-combustion carbon capture.