2024 AIChE Annual Meeting

(94a) Diffusion Kinetics of Gases in Porous Liquids

Authors

Qiu, L. Q., University of Tennessee
Mahurin, S., Oak Ridge National Laboratory
Dai, S., Oak Ridge National Laboratory
Porous liquids combine the permanent porosity of microporous solids and the fluidity of liquids. The paradoxical porous liquids are of great interest for both fundamental sciences and industrial applications. The synergistic combination of high adsorption capacities and fluidity has been explored for several applications like gas separations, gas storage, cascaded catalysis, etc. A great focus has been on tailoring the individual components toward sorption selectivity and capacity. Whereas the successful implementation of novel materials in industrial processes is also determined by the sorption kinetics.

In this work, we present the study of gaseous diffusivities in porous liquids. The diffusion of CO2 in porous liquids and the individual components was studied with both gravimetric measurements and pulsed-field gradient NMR (PFG-NMR). The numerical fitting of dynamic sorption data enables the computation of CO2 diffusivities at several equilibrium pressures. We also develop empirical correlations to predict effective diffusivities of gases in porous liquids analogous to mixed-matrix membranes. Additionally, PFG-NMR experiments of porous liquids and their components saturated with 13CO2 allow the evaluation of 13CO2 diffusion coefficients. Thus, an effective understanding of gas transport within porous liquids will contribute towards the targeted design and synthesis of porous liquids and accurate process modeling of porous liquids-based sorption.