Adsorption is widely used for gas storage and separation for industrial and environmental applications. With appropriate adsorbents adsorption represents a low-energy alternative to conventional separation technologies. Hybrid organic-inorganic materials offer the ability to tailor the pore geometry as well as the surface chemistry, which are the two governing properties of an adsorbent with respect to its adsorption behaviour. Thus they enable the design of specific adsorbents for gas separation processes. By means of molecular simulation, the adsorption behaviour can be predicted prior to manufacturing the material, reducing the effort of designing and/or screening of adsorbents significantly. This work focuses on two groups of hybrid materials. On the one hand, we studied aluminium methylphosphonates which are crystalline, organic-inorganic microporous materials. They can exhibit molecular sieving effects and as they are crystalline the atomic co-ordinates, which are necessary to perform molecular simulations of the adsorption process, can be derived accurately from XRD studies. On the other hand, organically modified, non-crystalline periodic mesoporous silicas (PMSs) can be prepared with different pore geometries and their mesopores are sufficiently large to accommodate even large surface groups. We have developed new methods to generate atomic models for the amorphous wall structure of PMSs by means of computer simulation of their synthesis. This so called kinetic Monte Carlo simulation is presented in combination with Grand Canonical Monte Carlo simulation of adsorption as a tool in a design procedure for adsorbents for gas separation. The application of these design tools is demonstrated by designing an MCM-41-type hybrid adsorbent for the removal of carbon dioxide from power-plant flue gas, and by optimising the process conditions for the separation of air into nitrogen and oxygen using microporous A1MePO-α.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:661646 |
| Date | January 2006 |
| Creators | Schumacher, Christian Carl |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/14360 |
Page generated in 0.0094 seconds