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EMERGING TECHNOLOGY BULLETIN: PHOTOELECTROCATALYTIC DEGRADATION AND REMOVAL OF ORGANIC AND INORGANIC CONTAMINANTS IN GROUND WATERS
Citation:
Gallardo*, V. EMERGING TECHNOLOGY BULLETIN: PHOTOELECTROCATALYTIC DEGRADATION AND REMOVAL OF ORGANIC AND INORGANIC CONTAMINANTS IN GROUND WATERS. EPA/540/F-01/502, 2001.
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Description:
Photocatalytic oxidation offers a means of remediating low concentrations of organics in aqueous and air streams. Commercial development of this technology is limited by relatively low rates of oxidation of organics in aqueous systems and by fouling of the catalyst by other components of the waste stream. Results from this project indicate that applying an appropriate electric field across the photocatalyst extends the range of applications for this technology. The resulting "biased" photoelectrocatalytic reactor demonstrates ca. 40-50% higher rates of degradation of the test organic (formic acid, initial concentration = 4-70 ppm as carbon) than are observed in the corresponding non-biased reactor. However, the overall rate of reaction is still slow even when biased: half-lifs of ca. 1 hour were observed. This biased reactor successfully treated a that contained both formic acid and dissolved copper. The biased reactor was not adversely affected by use in solutions with no dissolved oxygen or with high salt content (0.01-0.05 M NaCl). Non-biased reactors do not function under these conditions. Photoelectrodes that were stable during repeated use were prepared for this project by coating the photocatalyst on a metallic substrate: titanium.