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Research Projects in Dr. Winkelmann's Lab

Chemistry is so interesting because it explains why and how chemical processes occur. A chemical reaction occurs at a particular speed (rate) because of the pathway taken as reactants become products (the mechanism). My research focuses on understanding the reaction rates and mechanisms, an area of chemistry known as kinetics. I am especially interested in how light can affect chemical reactions (photochemistry). Kinetics affects every area of science, such as designing new materials, destroying environmental pollutants and understanding biological reactions.

If any of the projects described below interest you, please contact me by email or phone (674-7376). I would be happy to talk with you. Student researchers are a great help to me in the lab and you will gain valuable experience that you cannot get in class. Undergraduate students of any discipline are welcome. In fact, over the past year, I worked with students majoring in electrical engineering, chemical engineering, molecular biology and chemistry.

My research projects tend to overlap with other fields, such as environmental and materials chemistry, and so collaborations with other faculty are common. Current areas of interest include:

• TiO₂ Photocatalysis: Titanium dioxide is a biologically and environmentally inert material that becomes a catalyst when irradiated with UV light. Photolyzed TiO2 can oxidize or reduce surface-bound species, making TiO2 a common choice for the photocatalytic degradation of gaseous and aqueous pollutants. In some cases, visible light may also be used to initiate reactions. This is advantageous since the sun delivers far more visible light than UV light to us.

  My research in this area addresses the need for remediation of halogenated toxins, such as chlorofluorocarbons (CFCs), polychlorinated biphenyls (PCBs) and chemical warfare agents. For instance, photocatalytic reduction of CFCs can occur through a chain reaction that converts the CFC into its HCFC (hydrochlorofluorocarbon) analogue. This reaction is noteworthy since HCFCs are the industrial replacements for CFCs, which have been phased out.

  Research to study the dehalogenation of CFCs was funded by the Florida Solar Energy Center.

• Visible Light Actinometry: The efficiency of a photochemical reaction can be expressed as a ratio of the rate of the desired reaction to the rate of photons absorbed, or the photon flux.  Chemical actinometry is the science of measuring the photon flux using chemical reactions.  Several methods exist for measuring the flux of UV photons but fewer procedures have been established for visible light actinometry.  Since the sun's light mostly consists of photons within the visible range of the spectrum, visible light actinometry is necessary to measure the efficiency of solar energy processes.

  Several photochemical reactions are being studied as visible light chemical actinometers.  This research was supported through a grant from the Florida Solar Energy Center.

• Ferrate: Iron can exist in high oxidation states, including +6.  The ferrate ion (FeO₄^2-) is a particularly good oxidizer of pollutant molecules.  An added benefit of using ferrate is that the product, Fe(III), is environmentally benign.  This research is a collaboration with Dr. Virender Sharma and Dr. Tracy Gibson of ASRC Corp.

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