The combustion of fossil fuels over the past years has led to atmospheric accumulation of greenhouse gases that is a continuous threat of global warming. Carbon capture and seperation and natural gas technologies are promising solutions for reducing the release of greenhouse gas in the atmosphere. The high porosity, high thermal stability and unusually high chemical stability of zeolitic imidazolate frameworks (ZIFs) makes these materials ideal candidates for carbon capture and separation applications. We present results of computer simulations to study adsorption behavior in ZIFs. The simulations results agree well with our experimental data. Simulation was also performed to examine the ZIFs selectivity performance in a typical natural gas mixture composition (5% CO2 and 95% CH4). For ZIF-71, 93, and 97, the selectivity of CO2 is nearly independent of pressures, while when the pressure increases the selectivity decreases for ZIF-25 and increases for ZIF-96. At low pressure ZIF-25 is the most selective material whereas at high pressure ZIF-96 is more selective. We also studied water effect on gas adsorption in ZIFs. Based on calculated results, it is clearly shown that ZIF material can be divided into two types: hydrophobic and hydrophilic. For hydrophobic ZIFs (ZIF-25 and 71), water is barely adsorbed. Therefore, gas adsorption or selectivity is not affected by the existence of water. For hydrophilic ZIFs (ZIF-93, 94, 96, and 97), the pure gas adsorption is reduced in all ZIFs materials.

Molecular simulation of carbon capture and separation in a series of isoreticular zeolitic imidazolate materials

243rd National Meeting (2012)

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