1
Improving photocatalyst performance for water purification
through surface modifications
Katherine, Amanda Mather, Dr. Paul TratnyekAugust 20, 2010
Environmental and Biomolecular Systems
Oregon Health & Science University
Beaverton, OR 97006-8921 USA
http://ebs.ogi.edu
2The Shield 500
• Puralytics’ water purification device: “The Shield”• Grant from ONAMI
Source: The Oregonian
3The Shield 500: How it works
• Glass mesh• Titanium dioxide
4The Shield 500: How it works
5The Shield 500: How to Improve it
6Surface modifications
• Surface modifications may: – Change the selectivity or yield of contaminants– Increase range of wavelength response– Increase efficiency by inhibiting recombination
• Surface modifications tested: – Platinum– Silver– Gold– Palladium
7Experimental Procedures: Applying modification
• Photodeposition – 40 mL vials– Piece of TiO2 mesh (bare
or previously modified)– Metal reagent solution of
varying concentrations– Methanol as electron
donor– Solar simulator for 20
min.– Wash and dry pieces
while inside bottles
8Experimental Procedures: Testing modification
• Modifications to be tested by: – Same 40 mL vials as deposition– Piece of TiO2 mesh (bare or
previously modified)– Caffeine as model contaminant– Degraded under solar simulator– UV-Vis absorbance used for
analysis of degradation
9Results: Caffeine Degradation
10Results: Optimum Loading
11Conclusions
Platinum surface modification, while using H2PtCl6 as a reagent solution, provides the largest improvement in photocatalyst performance and should be tested in The Shield 500 reactor.
12Acknowledgements
Thank you to Amanda Mather, Dr. Paul Tratnyek, CMOP, and Saturday Academy’s Apprenticeships in
Science and Engineering.
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Supplemental Slides
14Experimental Procedures: Applying modification
• Gold deposited TiO2 of various loadings
15Caffeine
16Solar Bag