Separation of nitrogen dioxide from the gas mixture with nitrogen by use of ZIF materials; computer simulation studies

Abstract The separation of nitrogen dioxide (NO 2 ) from the gas mixture with nitrogen (N 2 ) by selective adsorption and diffusion in three Zeolitic Imidazolate Frameworks (ZIFs) is examined by Gibbs Ensemble Monte Carlo (GEMC) and Molecular Dynamics (MD) computer simulations at 373 K, which is a temperature that can be found in the exhaust gases of combustion engines and furnaces. This temperature ensures that the chemical equilibrium reaction between NO 2 and N 2 O 4 can be neglected since at this temperature almost only NO 2 exists. At 373 K, the membrane selectivity of NO 2 over N 2 is predicted to be about 4.2 (ZIF-90), 5.2 (ZIF-8), and 10.6 (ZIF-78). In addition, it is shown that N 2 O 4 can be neither adsorbed nor diffuses inside these ZIF materials, which makes these ZIFs a promising materials for separation by membranes. Due to molecular sieving, only N 2 and NO 2 can pass the ZIF membranes.