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Title: In-situ FTIR studies of the solid oxide-CO2 interface
Author: Wain, C. I.
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2007
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In the present work, nitrogen adsorption and thermo-gravimetric analysis have been conducted, along with in-situ FTIR spectroscopic measurements in order to investigate the desiccation process of scCO2 on the surface of solid oxides such as silica EP10, silica EP12, aerosol 200, γ-alumina, zeolite HUSY and Cu/silica. The relationship between the integrated area of the OH deformation mode of molecularly adsorbed water on the solid oxides and the correspondent water content was initially established for each of the materials of interest at atmospheric pressure. Then, at high pressures, calibration curves were obtained in order to quantify the amount of water dissolved in liquid and scCO2. Finally, FTIR spectra were simultaneously recorded of the solid and the fluid phase, which allowed for a closer examination of the behaviour of the water. For all oxides (except zeolite HUSY), results demonstrated that water was transferred from the solid phase to liquid and scCO2. This process was generally more effective under liquid CO2. The calculated total amount of water lost by the solid oxide was in all cases apparently greater than the total amount of water gained by the fluid phase. Additionally, the total amount of water dissolved in liquid and scCO2 was always less than the expected solubility value given by published data. Silica EP10 (S.A. = 230 m2 g-1) presented the highest quantity of water transferred into the fluid phase, while γ-alumina (S.A. = 104 m2 g-1) transferred the lower quantity. This demonstrated that the amount of water transferred during liquid and scCO2 exposure was not completely independent of the surface area of the solid, or of the pore size and shape. It is highly likely that the extent of the water transfer is directly related to the density differences within the pore and bulk of the fluid phase.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available