Cleaning up the water supply using photolysis to destroy trace waterborne contaminants
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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
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
Overall Research Objective Trace Waterborne Contaminants

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


Goals
Goals Trace Waterborne Contaminants

  • 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


Background
Background Trace Waterborne Contaminants

  • 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


Basic reaction mechanism
Basic Reaction Mechanism Trace Waterborne Contaminants


Research methods

Reactor Trace Waterborne Contaminants

Lamp outlet

Research Methods

Xe M-U-T Lamp & Reactor

Solar Experiments

Tubular UV Reactor

Size:

20 mL

600 mL

30 L

Intensity:


Xe lamp experiments
Xe Lamp Experiments Trace Waterborne Contaminants

  • Over period of 20 hours, 75% of target compound destroyed

  • Can calculate reaction rate from plot


Solar experiments
Solar Experiments Trace Waterborne Contaminants

  • Effect of increasing H2O2 concentrations on the degradation of nonylphenol (left)

  • Effect of isopropanol (hydroxyl radical scavenger) on photolysis rate (right)


Tubular uv reactor experiments
Tubular UV Reactor Experiments Trace Waterborne Contaminants

  • 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


Conclusions
Conclusions Trace Waterborne Contaminants

  • 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.


Thanks to
Thanks to . . . Trace Waterborne Contaminants

  • 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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