(641e) CO/N2 Separation Using MOFs: Investigation of the Role of Metal Type and Metal Density

Carbon monoxide (CO)/Nitrogen (N₂) separation is a particularly challenging separation, yet one with great industrial relevance for the synthesis of high-value chemicals. While an expensive cryogenic step can be used to perform such separation, it remains ineffective in purifying CO from syngas streams with high concentrations of N₂.

Taking advantage of the lower energy requirement of adsorption processes, we have explored the use of metal-organic frameworks (MOFs) as adsorbents for this challenging separation. Due to the multitude of possible MOF structure, we used a multi-scale approach – combining molecular simulation and process system modelling – to identify suitable MOFs for the targeted separation. We will present our work on a particular sub-set of MOFs, i.e. MOF-74 family. The effect of different types of metals as part of the MOF structure or impregnated on their surface was evaluated. The materials were characterised by analytical, spectroscopic and imaging tools and their performance in terms of capacity and selectivity was evaluated using dynamic and equilibrium tests. High recovery and purity of the CO stream were achieved, though variations were observed depending on the type of metals. The trends enabled to identify the adsorption mechanisms and guide the design of new MOF structures.