Improving photocatalyst performance for water purification through surface modifications Katherine, Amanda Mather, Dr. Paul Tratnyek August 20, 2010 Environmental and Biomolecular Systems Oregon Health & Science University Beaverton, OR 97006-8921 USA http://ebs.ogi.edu
The Shield 500 • Puralytics’ water purification device: “The Shield” • Grant from ONAMI Source: The Oregonian
The Shield 500: How it works • Glass mesh • Titanium dioxide
Surface modifications • Surface modifications tested: • Platinum • Silver • Gold • Palladium • Surface modifications may: • Change the selectivity or yield of contaminants • Increase range of wavelength response • Increase efficiency by inhibiting recombination
Experimental 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
Experimental 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
Conclusions 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.
Acknowledgements Thank you to Amanda Mather, Dr. Paul Tratnyek, CMOP, and Saturday Academy’s Apprenticeships in Science and Engineering.
Experimental Procedures: Applying modification • Gold deposited TiO2 of various loadings