Inactivation of Airborne Bacterial Spores Using Different Titanium Dioxide Coatings

O. M. ALFANO; S. M. ZACARÍAS; M. C. VACCARI; M. L. SATUF

Oporto

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

SPEA

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.