(211f) Optimising adsorption-desorption cycles with flexible Metal Organic Frameworks

Quite a number of Metal Organic Frameworks have a flexible framework. In presence of external stimuli, their structure changes, resulting in a change of pore volume and pore size and thus adsorption properties. This change can be drastic, e.g. the transition from a narrow pore form to a large pore form at a critical pressure or rather gradual i.e. the swelling of a structure with increasing degree of pore filling. Such flexible materials often show unusual isotherms, with sometimes very steep steps and an hysteresis loop in the adsorption and desorption isotherms. In this paper, we analyse how the desorption of molecules from such a flexible MOF with a stepped isotherm showing hysteresis can be made more efficient.