Simulating Local Adsorption Isotherms in Structurally Complex Porous Materials: A Direct Assessment of the Slit Pore Model

A fundamental understanding of the behavior of fluids confined in structurally complex nanoporous materials is crucial to the development of improved technologies for environmental remediation and energy storage. We present a computational method for assessing the impact that confinement has on the properties of fluids in model porous materials. The proposed method is demonstrated by calculating pore-size-specific adsorption isotherms and adsorption selectivites in a structurally heterogeneous nanoporous carbon (NPC) model. The results from this method are used to test the predictions made by the ubiquitous slit pore (SP) model. In general, we find that the SP model does not qualitatively capture the behavior of the pore-size-specific adsorption isotherms and selectivites in the NPC structure. These qualitative differences provide significant insight into the origins of the well-known deficiencies of the SP model to predict the adsorption behavior of real NPCs.