Predicting the Capability of Metal Organic Frameworks to Selectively Pre-Concentrate Energetic Molecules
Ruichang Xiong1, Jared T Fern1, David J. Keffer1, Miguel A. Fuentes-Cabrera2, and Don M. Nicholson3. (1) Chemical Engineering, University of Tennessee, 419 Dougherty Hall, Knoxville, TN 37996-2200, (2) Joint Institute for Computational Science, University of Tennessee and Oak Ridge National Laboratory, (3) Computer Science and Mathematics Division, Oak Ridge National Laboratory
In order for explosive molecules to be detected, the amount delivered to a sensor must exceed its detection threshold. Pre-concentrators facilitate this process by extracting explosive molecules from the atmosphere and delivering them to sensors in amounts required for reliable detection. Current pre-concentrators are not very selective and hence deliver material that is predominately contaminant. With the ability to tailor Metal Organic Frameworks (MOFs), there is hope that a pre-concentrator can be designed to selectively adsorb explosive molecules in the presence of contaminants. In order to test the feasibility of selectively pre-concentrating explosive molecules for detection, molecular simulations of RDX and TATP within different MOFs were performed with and without contaminants. The simulations give new insight into the competitive nature of the adsorption and the binding of the explosive molecules to the framework. Adsorption isotherms, mobility of the RDX within the framework, the occupancy of each type of cage within the unit cell, and the framework's effect on the configuration of the explosive molecules were investigated by grand canonical Monte Carlo (GCMC) and molecular dynamics (MD).