Abstract :
Photocatalysis by titanium dioxide (TiO2), operational in the UV-A domain with a potential use of solar radiation,
could be an alternative to conventional water detoxification and disinfection technologies. However, employing the photocatalyst
as a suspension or slurry makes the scaling-up of the process difficult, as the TiO2 has to be removed from the
decontaminated water to be reused several times. In this work the photocatalytic activity of different types of TiO2 catalyst
(Degussa P-25, Millennium PC-100 and PC-500, Tayca AMT-100 and AMT-600) in suspension or coated on fibrous web
were studied in both decontamination and disinfection experiments at laboratory scale. Gallic acid was chosen as the
model pollutant for detoxification experiments and Escherichia coli as the model microorganism for disinfection experiments.
The influence of the surface area and other characteristics of TiO2 are discussed concerning the photocatalytic properties
of TiO2. The role of adsorption is suggested, indicating that the reaction occurs at the TiO2 surface and not in the
solution. Gallic acid degradation kinetics were found to be of the same extent for both TiO2 suspended and fixed, whereas
for the bacterial inactivation efficiency was significantly less important with coated than with suspended TiO2.
2005 Elsevier Ltd. All rights reserved.
