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TiO2 photocatalyst poisoning/contamination TAP project


EMSL Project ID
44650

Abstract

Puralytics makes a water treatment system using UV-activated photoctalysis to remove organic and other contaminates from water. The photocatalytic material is becoming de-activated/contaminated by contact with tap water. After a few hundreds of gallons of tap water flow through the catalysts material we observe browning of the photocatalysts and as much as a 90% reduction in photcatalytic efficiency in removing organics. Use of activated carbon and particulate filters have not eliminated the problem SEM and other characterization tools available to Puralytics have indicated that the brown material is organic, but have been unable to identify the root cause of the deactivation-Puralytics’ wants to know if the browning is a root cause or a result of the root cause. SEM and other tools used to date depend on testing the photocatalyst in a vacuum, so that water-born and volatile materials are removed before testing can occur. Puralytics needs access to better tools and with technical assistance.

Our hypothesis is that this is due to specific poisoning of the catalyst by deposition of either metals (e.g., iron) or "scale" forming phases (e.g., Ca and Mg salts) on the TiO2. This needs to be confirmed by use of the following characterization techniques.

Project Details

Start Date
2011-04-11
End Date
2012-04-15
Status
Closed

Team

Principal Investigator

Mark Engelhard
Institution
Environmental Molecular Sciences Laboratory

Team Members

Zihua Zhu
Institution
Environmental Molecular Sciences Laboratory

Theva Thevuthasan
Institution
Environmental Molecular Sciences Laboratory