Limitations and high pressure behavior of MOF-5 for CO2 capture

Abstract

Porous network structures (e.g. metal–organic frameworks, MOFs) show considerable potential in dethroning monoethanol amine (MEA) from being the dominant scrubber for CO₂ at the fossil-fuel-burning power generators. In contrast to their promise, structural stability and high-pressure behavior of MOFs are not well documented. We herein report moisture stability, mechanical properties and high-pressure compression on a model MOF structure, MOF-5. Our results show that MOF-5 can endure all tested pressures (0–225 bar) without losing its structural integrity, however, its moist air stability points at a 3.5 hour safety window (at 21.6 °C and 49% humidity) for an efficient CO₂ capture. Isosteric heats of CO₂ adsorption at high pressures show moderate interaction energy between CO₂ molecules and the MOF-5 sorbent, which combined with the large sorption ability of MOF-5 in the studied pressure–temperature ranges show the viability of this sorbent for CO₂ capturing purposes. The combination of the physicochemical methods we used suggests a generalized analytical standard for measuring viability in CO₂ capture operations.