We are using MD simulations and DFT calculations to predict O2/N2 separations in novel metal-organic frameworks (MOFs). The environmental impact of coal-based power plants can be greatly reduced by burning oxygen-enriched gas rather than air. By reducing the amount of nitrogen in the combustion gas, coal power plants can burn with a smaller volume of combustion gas, resulting in higher flame temperatures, greater thermal efficiency, greatly reduced exhaust gas volumes, reduction of NOx emissions, and increased efficiency of CO2 emission capture. There are currently two primary methods for generating oxygen-enriched air � cryogenic separation and pressure-swing adsorption � but both have considerable limitations. With their high porosity, large specific surface areas, and tunable pore sizes, MOFs are excellent candidates for the separation of oxygen from air. We have screened known and theoretical MOFs for preferential adsorption of oxygen over nitrogen, based on Henry's constants and pore size considerations. MOFs identified in the screening were selected for GCMC simulations to predict oxygen and nitrogen adsorption isotherms, and these results were compared to experimental isotherms for validity. DFT calculations were performed to determine the binding energy of oxygen on various coordinatively unsaturated metal sites (CUS) and to examine the role of the electronic structure of the metal in selective oxygen adsorption. The simulations will help guide rational design of new MOFs. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U. S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Metal-organic frameworks for oxygen-enrichment of air: Insights from molecular simulation

246th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.