Environmental Engineering Science Seminar
Lopata 101
Friday, April 14, 2006
Time: 11 am
Advanced Oxidation Technologies and Nanotechnologies for Water Treatment: Development and Application in the Destruction of Cyanobacterial Toxins
ABSTRACT
The enormous diversity of toxic and organic pollutants of different chemical composition eliminates the possibility of using a universal treatment method and has led to the development of special treatment methods for water decontamination. The so-called Advanced Oxidation Technologies (AOTs) and Nanotechnologies (AONs) are among the most promising emerging chemical oxidation processes and are anticipated to play a crucial role in water treatment as stand-alone processes or in combination with conventional technologies. Among AONs, TiO2 photocatalysis is of particular interest because of environmentally friendly features. TiO2 photocatalysis is characterized by a specific oxidation pathway, which includes the formation of hydroxyl radicals (●OH) or other powerful oxidizing species. The hydroxyl radicals are extremely reactive and readily attack most organic contaminants. As a result, the organic contaminants are sequentially transformed to simpler organic molecules that are eventually mineralized to CO2, H2O, and mineral species (i.e., Cl). In general, due to rapid hydroxyl-radical-based oxidation reactions, AONs are characterized by high reaction rates and short treatment times.
Dr. Dionysiou will discuss some general aspects of AOTs, examples of destruction of organic contaminants using hydroxyl radicals and sulfate radicals, as well as TiO2-based AONs for the treatment and purification of water in general and in particular for the destruction of cyanobacterial toxins. He will discuss the development of a TiO2 photocatalytic technology using novel nanotechnology and self-assembling strategies. Results will also be presented on the synthesis of TiO2 catalyst in the form on films, and membranes and the application of these materials on the destruction of microcystin-LR, a potent cyanobacterial hepatotoxin.
Short Biographic Sketch of the Speaker
Professor Dionysiou was born in the Island of Cyprus, which is a small Island (800,000 inhabitants) in the Eastern part of the Mediterranean Sea. He holds a Diploma (B.S./short M.S., 1991) from National Technical University of Athens, Greece and a M.S. degree (1995) from Tufts University, both in Chemical Engineering. His Diploma thesis work focused on Biotechnology whereas his M.S. work focused on Crystallization. He obtained his Ph.D. in Environmental Engineering at the Department of Civil and Environmental Engineering, University of Cincinnati (2001). His Ph.D. work focused on TiO2 Photocatalysis. Dr. Dionysiou has industrial experience (1994-1995) with W. R. Grace, Masonry Product Division where he performed research on the effects of non-ionic and ionic surfactants on the stability of colloidal systems used in construction products. He is currently an Associate Professor in the Division of Environmental Engineering and Science at the Department of Civil and Environmental Engineering, University of Cincinnati.
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