Sensitized photocatalytical oxidation of s-triazine herbicides

For effective and economic water treatment emphasis has been placed on solarchemical degradation techniques. The photocatalytical oxidation (PCO) of contaminants on semiconductor surfaces with solar light as energy source proves to be an effective method of water purification, but such systems using titanium dioxide as photocatalyst can utilize only 5% of the solar energy reaching the surface of the earth because of the large bandgap of the semiconductor. In this connection, dye sensitization has been found to be a promising way for extending the spectral response of the titanium dioxide catalyst to longer wavelength (SPCO). The sensitization in the SPCO process was carried out with rose bengal or ruthenium dyes as sensitizer, respectively, and using titanium dioxide as photocatalyst. For the first time several triazine herbicides could be decomposed by SPCO applying only visible light.