Master of Science / Department of Chemistry / Kenneth Klabunde / Remediation of the indoor environment led to the development of novel catalysts which can absorb light in the visible range. These catalysts were prepared using the wet chemistry method known as sol-gel chemistry because preparation via sol-gel provides a homogeneous gel formation, which can be treated via supercritical drying to produce an aerogel. These aerogels have been found to have high surface areas when a combination of titania/silica is used. The increase in surface area has been shown to enhance the activity of the catalysts. Mixed metal oxide systems were prepared using titanium isopropoxide and tetraethyl orthosilicate to yield a 1:1 system of titania/silica (TiO2/SiO2). These systems were doped during the initial synthesis with transition metals (Mn or Co) to create mixed metal oxide systems which absorb light in the
visible light range. These materials were assessed for potential as heterogeneous catalysts via gas-solid phase reactions with acetaldehyde. Degradation of acetaldehyde as well as the
formation of CO2 was monitored via gas chromatography-mass spectrometery. To increase the activity, visible light was introduced to the system. Experiments have shown that a 10 mol %
manganese doped titania/silica system, in the presence of light, can degrade acetaldehyde. The
cobalt doped counterpart showed dark activity in the presence of acetaldehyde resulting in the
formation of CO2 without the addition of visible light. In the hope of increasing surface area a
mixed solvent (toluene/methanol) synthesis procedure was applied to the manganese doped
catalyst. The resulting materials were of a low surface area but showed a significant increase in
degradation of acetaldehyde.
Examination of the interactions between mixed metal oxide systems and semivolatile
organic compounds (SVOCs) was studied. The pollutant, triphenyl phosphate, was dissolved in
n-pentane and exposed to 10 mg of a given catalyst. These reactions were monitored using UVVis. All systems but the manganese doped titania/silica system resulted in the observation of no activity with triphenyl phosphate. The manganese doped catalyst shown a peculiar activity, the increase in absorbance of the triphenyl phosphate peaks as well as the formation of a new peak.
| Identifer | oai:union.ndltd.org:KSU/oai:krex.k-state.edu:2097/13348 |
| Date | January 1900 |
| Creators | Baker, Schuyler Denton |
| Publisher | Kansas State University |
| Source Sets | K-State Research Exchange |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
Page generated in 0.0021 seconds