The adsorption of mixtures of polar and non-polar species is influenced by both the structure and the surface chemistry of the adsorbent. Several molecular simulation techniques have been employed to study the effect of these factors on the extent and mechanism of adsorption of water and light hydrocarbons. In particular, the effect of pore size as well as the concentration, distribution and type of polar surface groups have been examined in a detailed and systematic way. It is shown in this thesis that the presence of polar sites on the surface of the carbon enhances the affinity of the adsorbent towards water. However, in most situations of practical interest, the most important variable was seen to be the concentration of polar sites, with their distribution and type playing only a minor part. This fundamental study formed a basis for the development of a model for activated carbon that can be used in an industrial context. The model for activated carbon includes a representation of the structure of the adsorbent using a distribution of slit-shaped pores, and of the surface chemistry, using a distribution of polar sites. The adsorption in single pores was calculated by grand canonical Monte Carlo simulation. The pore size distribution was obtained from an analysis of pure-ethane adsorption isotherms, while the polar site distribution was calculated by analysing pure-water adsorption. The performance of the model was assessed by comparing the simulated results for binary water/ethane adsorption with experimental adsorption data on a commercial activated carbon. The sensitivity of the predictions to changes in the surface chemistry of the model was examined. The model proposed here was seen to perform much better than the more widely used classical methods, opening good prospects for its use in industrial applications.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:653156 |
| Date | January 2003 |
| Creators | Jorge, Miguel Angelo da Silva |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/12321 |
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