(506a) Assessment of Metal Organic Framework Membranes for Carbon Dioxide Separations Using Atomically Detailed Simulations

Membrane technology is economically competitive with alternative separation technologies such as distillation, crystallization, absorption, or solvent extraction for many chemical separations. Although polymeric membranes are widely available for CO2 separation applications, they possess a fundamental trade-off between selectivity and throughput. New materials with fundamentally different adsorption and transport properties are required to develop high efficiency membranes suitable for large volume applications such as CO2 capture. Metal-organic frameworks (MOFs) have enormous potential as membranes for large-scale gas separations because of their potential for rational design of micropore size, shape, and functionality yet almost nothing is currently known about the performance of MOFs as membranes.

The aim of our work is to introduce an efficient approximate method for screening MOFs based on atomistic models that will accelerate the modeling of membrane applications. The validity of this approximate method is examined by comparison with our previous detailed calculations for CO2/CH4 and CO2/H2 mixtures at room temperature permeating through IRMOF-1 and CuBTC membranes. These results allow us to hypothesize a connection between two computationally efficient correlations predicting mixture adsorption and mixture self diffusion properties and the validity of our approximate screening method. We study the potential of various MOFs, including IRMOF-1, -8, -9, -10 and -14, CuBTC, COF-102 and Zn(bdc)(ted)0.5 to examine the effect of chemical diversity and interpenetration on the performance of MOF membranes for CO2 separations. We will show how insight from these initial calculations can be used to choose candidate materials from the very large number of MOFs that are known for specific membrane applications.