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