ENVR 282 |
| Plasma, typically considered a highly ionized gas, can be formed by high voltage electrical discharges in systems with large amounts of water. These systems are excellent sources of many active radical and molecular species for water treatment. Significant amounts of species such as hydrogen peroxide and hydroxyl radicals that are formed in such discharges, degrade a number of organic compounds and inactivate microbes. The combinations of chemical, thermal, and physical factors (including UV light formation) caused by the electrical discharge can lead to very effective water cleaning. A number of different of types of plasma reactors, including those with discharges over water surfaces, discharges directly in the water, discharges with water sprayed through the plasma, discharges with gases bubbled through the liquid, and various combinations of these, have been attempted. The addition of catalysts has also been shown to lead to enhanced organic compound destruction. Recent work has found highly efficient production of hydrogen peroxide in water spray and effective destruction of organic compounds through gliding arc discharges with pulsed power. Higher energy gliding arc discharges with AC power can lead to effect mineralization or total organic carbon removal of complex dyes. A gliding arc discharge is formed when a gas flows through a region of two or more knife-shaped electrodes, whereby the flowing gas stabilizes the discharge. When water is injected into the flowing gas as a spray, the electrical discharge leads to water dissociation in the high temperature plasma zone and subsequent radical combination in the cooler zones of the discharge lead to molecular species formation. This talk will focus on analysis and optimization of gliding arc discharge reactors for the formation of active chemical species, particularly hydrogen peroxide. |
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Advances in Abiotic Transformation Processes for Micropollutants in Drinking Water and for Sourcewater Protection
6:00 PM-8:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster
Division of Environmental Chemistry |