Inactivation of Airborne Bacterial Spores using Different Titanium Dioxide Coatings

ALFANO, O.M.; ZACARIAS, S.M.; VACCARI, M.; SATUF, M.L.

Congreso; 7th European Meeting on Solar Chemistry and Photocatalysis: Environmental Applications-SPEA7; 2012

The performances of three different TiO2 coatings (Degussa P- 25, Sol-Gel and Sol-Gel/Degussa P-25) and the influence of the increase in the TiO2 layer thickness were compared for the photocatalytic inactivation of dry Bacillus subtilis spores dispersed on TiO2 films and irradiated with UV-A radiation (1.89 mW cm-2) during different periods of time. The highest inactivation rate of B. subtilis spores was obtained when they were irradiated on plates coated with two layers of TiO2 Degussa P-25 (99.77 % of inactivation). We also obtained 94.93 % of inactivation over Sol-Gel/Degussa P-25 catalyst (two layers), and 80.60 % of inactivation over Sol-Gel catalyst (three layers). Two kinds of efficiencies were also evaluated, the apparent photonic efficiency and the quantum efficiency of inactivation.