(571g) Investigation of Departures from Ideal Adsorption Behavior by Binary Gas Mixtures on Metal-Organic Framework Adsorbents

Understanding behavior of separation systems under realistic conditions is a key to advancing separation science. Separation by adsorption is an active area of research and offers opportunity for tremendous energy savings over legacy separation methods. Development of adsorbent materials is an area of intense focus in adsorption separations research, but often this focus overshadows the equally pressing need to understand how adsorbent materials interact with complex mixtures. Presently, the study of gas separation by adsorption is overly reliant on the Ideal Adsorbed Solution Theory (IAST) to predict mixed gas adsorption using pure gas adsorption experiments alone. As metal-organic frameworks (MOFs) have become an adsorbent class of strong interest for adsorption separations, it is increasingly important to consider that IAST is especially prone to error in predicting mixture adsorption on MOFs. While the study of pure gas adsorption on isostructural MOFs incorporating different pore chemistries has yielded rich information relating to pure gas adsorption, relatively little is known about how pore chemistry affects adsorption of mixtures. In this work, a group of three MOFs is used as a platform to investigate the effects of energetic heterogeneity of the adsorbent surface on adsorption of mixtures and departure from IAST behavior. This work builds on a previous study describing construction of an automated volumetric instrument for mixture adsorption measurement.

Figure 1. MOF frameworks, adsorbate molecules, and home-built automated volumetric multi-component adsorption instrument used in this work.

Parts of abstract figure from

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