Kuvvet alanı paramatrelerinin ZIFlerin gaz ayırımı performansları üzerine etkisi

Metal organic frameworks (MOFs) are newly emerging promising candidates for gas separation and gas storage. Zeolitic imidazolate frameworks (ZIFs) are highly robust sub-family of MOFs and they have large surface areas, high porosities and well-defined pore structures. In the first part of this thesis, Grand Canonical Monte Carlo (GCMC) and Equilibrium molecular dynamics (EMD) simulations are used and a diverse collection of ZIFs are studied to evaluate their performances in adsorption- and membrane-based gas separations. These molecular simulations are performed for both single- component gases (CH4, CO2, H2 and N2) and binary gas mixtures (CO2/CH4, CO2/N2, CO2/H2 and CH4/H2) to predict the intrinsic and mixture selectivities of ZIFs. These two selectivities are compared to discuss the importance of multi-component mixture effects on making predictions about the separation performance of a material. Gas separation performances of ZIFs are compared with other nanoporous materials and results show that several ZIFs can outperform well-known zeolites and metal-organic frameworks in CO2 separations. Several other properties of ZIFs such as gas permeability, working capacity and sorbent selection parameter are computed to identify the most promising materials in adsorption- and membrane-based separation of CO2/CH4, CO2/N2, CO2/H2 and CH4/H2. In the second part, the effect of different force field parameters on the selectivity estimation is examined. In the literature, a significant number of molecular simulation studies exists for assessing single-component gas adsorption capacities of ZIFs and all these simulations are performed using different force field parameters. Molecular simulations are carried out to predict both adsorption-based and membrane-based separation performances of ZIF-68 and ZIF-69 for CH4/H2, CH4/N2, CO2/CH4, CO2/N2 and CO2/H2 mixtures using three different force fields. Results show that adsorption selectivity of ZIFs may vary significantly depending on the force field parameters whereas membrane selectivity is much less sensitive to the force field. In addition to adsorption and membrane selectivities, various separation properties of ZIFs are estimated such as working capacity, sorbent selection parameter, regenerability, permeability and compared with the properties of other well-known nanoporous adsorbents and membranes. Results suggest that ZIF-68 and ZIF-69 can outperform traditional zeolites in separation of CH4/H2 and CO2/H2 mixtures