Adsorbent ve membran metal organik yapıların moleküler simülasyonlar kullanılarak verimli sıralanması

In this thesis, efficient ranking methods for promising metal organic framework (MOF) adsorbents and membranes were defined using molecular simulations. First, MOF adsorbents that can efficiently separate CO2 from natural gas (CO2/CH4), power plant flue gas (CO2/N2) and petroleum refineries (CO2/H2) were investigated. Several adsorbent evaluation metrics including selectivity, working capacity, adsorption figure of merit, sorbent selection parameter, per cent regenerability were computed for 100 different MOFs and for each gas separation. Results showed that regenerability is a very important metric to screen the materials at the first step of the adsorbent search and MOFs can be then ranked based on their selectivities. In the second part of thesis, gas permeability and selectivity of 700 new mixed matrix membranes (MMMs) composed of 70 different MOFs and 10 different polymers were calculated for CO2/N2 separations. This was the largest number of MOF-based MMMs for which computational screening was done to date. Selecting the appropriate MOFs as filler particles in polymers resulted in MMMs that have higher CO2/N2 selectivities and higher CO2 permeabilities compared to pure polymer membranes. It was found that for polymers that have low CO2 permeabilities but high CO2 selectivities, the identity of the MOF used as filler is not important. The outcome of adsorbent evaluation and membrane evaluation results were then applied for nitrogen separation from methane (CH4/N2). Combined adsorption and diffusion data obtained from molecular simulations were used to predict both membrane selectivities and gas permeabilities of 102 MOFs for separation of CH4/N2 mixtures. The relations between easily computable structural properties such as pore sizes, surface areas and porosities of MOFs and performance evaluation metrics were also examined to provide structure-property relationships that can serve as a guide for experimental studies.