Moleküler simülasyonlar ve teorik korelasyonlar kullanarak soy gazların MOF'lardaki adsorpsiyon, difüzyon ve ayırımlarının hesaplanması

Atomically detailed simulations have been widely used to assess gas storage and gas separation properties of nanoporous materials. Metal organic frameworks (MOFs) are new potential candidates for gas separation applications due to their well defined pore structures, large surface areas and porosities. In the first part of this thesis, grand canonical Monte Carlo (GCMC) and equilibrium molecular dynamics (EMD) simulations were used to compute adsorption and diffusion of noble gases, Xe, Kr, Ar and their binary mixtures in several MOFs. Ten representative MOFs having different metal sites, organic linkers, topologies and pore sizes were chosen to examine the effects of structural properties of MOFs on their noble gas separation performances. Several properties of MOFs such as adsorption selectivity, working capacity, diffusion selectivity, permeation selectivity, and gas permeability were evaluated and compared with those of traditional nanoporous materials. Results showed that several MOFs exhibit higher selectivities than traditional zeolites in adsorption-based separation of Xe/Kr and Xe/Ar mixtures. According to simulation results, MOFs are promising candidates for Xe/Kr and Xe/Ar separations due to their high Xe selectivity and permeability. In the second part, Krishna-Paschek (KP) correlations and Ideal Adsorbed Solution Theory (IAST) were applied to predict self-diffusivities and adsorption isotherms of Xe/Kr and Xe/Ar mixtures at various compositions, respectively. These predictions were then compared with the results of molecular simulations obtained in the first part. Gas permeabilities and selectivities of MOFs obtained from theoretical correlations were compared with the ones obtained from simulations and reasons for deviations were discussed. Our results suggested that theoretical correlations can make accurate predictions and can be used instead of detailed molecular simulations for initial screening of MOFs in noble gas separation applications.