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Cleaning Up the Water Supply: Using Photolysis to Destroy Trace Waterborne Contaminants

Cleaning Up the Water Supply: Using Photolysis to Destroy Trace Waterborne Contaminants. Presented by Daniel Whitley Project Mentor: Dr. Eduardo Saez NASA Space Grant Symposium April 17, 2010. Overall Research Objective.

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Cleaning Up the Water Supply: Using Photolysis to Destroy Trace Waterborne Contaminants

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  1. Cleaning Up the Water Supply: Using Photolysis to Destroy Trace Waterborne Contaminants Presented by Daniel Whitley Project Mentor: Dr. Eduardo Saez NASA Space Grant Symposium April 17, 2010

  2. Overall Research Objective To improve water quality through the removal of trace organic contaminants using an inexpensive, easily implementable, scalable process Image Courtesy of The South African State of Rivers Report: uMngeni and Neighboring Rivers and Streams http://www.dwa. gov.za/iwqs/rhp/state_of_rivers/state_of_umngeni_02/umngeni.html

  3. Goals • Identify Organic Contaminants: Nonylphenol, p-Cresol, Aniline • Identify Method: UV Photolysis • Characterize Photolysis & H2O2 Photolysis Rates of Different Compounds • Quantify Rates of Degradation at Different Scales

  4. Background • Nonylphenol, cresols, and other phenolic compounds have a variety of household and industrial uses • These compounds (or their precursors) often get dumped into rivers and lakes, and can survive traditional effluent treatment methods Coater at the Madawaska Maine Fraser Paper Mill. Image courtesy of Studio Laporte http://www.toucherdubois.ca/tdb/page.php?menu=20 • These compounds are endocrine disruptors, harming wildlife and possibly even people

  5. Basic Reaction Mechanism

  6. Reactor Lamp outlet Research Methods Xe M-U-T Lamp & Reactor Solar Experiments Tubular UV Reactor Size: 20 mL 600 mL 30 L Intensity:

  7. Xe Lamp Experiments • Over period of 20 hours, 75% of target compound destroyed • Can calculate reaction rate from plot

  8. Solar Experiments • Effect of increasing H2O2 concentrations on the degradation of nonylphenol (left) • Effect of isopropanol (hydroxyl radical scavenger) on photolysis rate (right)

  9. Tubular UV Reactor Experiments • High light intensity means target compound degradation through H2O2 photolysis occurs very fast • Direct photolysis (no H2O2) starts fast but then slows as byproduct forms, absorbing light and thus reducing available photons μ

  10. Conclusions • H2O2 photolysis using ultraviolet light is effective in destroying nonylphenol, p-cresol, and any other compound that reacts with OH•. • High intensity ultraviolet sources can degrade organic compounds directly (direct photolysis), albeit at a slower rate than with H2O2 photolysis. • Hydroxyl radical scavengers can slow the rate of reaction of the compound of interest.

  11. Thanks to . . . • My Professors: Dr. Eduardo Saez and Dr. Robert Arnold • My Research Team: Mario Rojas, Fernando Perez, Amy Gobel, and Cary Leung • The Atmospheric Sciences Department, especially Eric Betterton and Brian Barbaris • And the NASA Space Grant Internship Program for making it all possible!

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