Using Metal-Organic Frameworks for CO Purification: Investigation of Key Material Parameters through a Multi-Scale Approach

Carbon Monoxide (CO) production for industrial use is currently accompanied with an energy-intensive separation process. Indeed, its downstream separation from synthesis gas (syngas), a mixture of CO and H₂ as well as impurities like nitrogen, carbon dioxide and water, is a multi-step process involving a cryogenic distillation section aimed at separating CO from H₂. Due to similar sizes, molecular weights and boiling points, it is particularly difficult to separate CO and N₂. Therefore, an expensive cryogenic step is required, and still remains ineffective in purifying CO from syngas streams with high concentrations of N₂. Adsorption separation has the potential to become a more economical alternative.

This study investigates the use of a class of adsorbents, namely metal-organic frameworks (MOFs), for purification and separation of CO from gas streams containing high levels of N₂. Due to the multitude of MOFs that exist, a multi-scale approach - combining molecular simulation and process system modelling - proposed suitable MOFs for the targeted separation. In this presentation, we will show a number of promising MOF structures that were identified, synthesized, characterized and tested for CO adsorption under both equilibrium and dynamic conditions. The effects of the porosity, type of metal sites, group functionalization and incorporation of additional chemisorption sites on the uptake and selectivity were investigated and will be discussed during the talk.