Evaluation of different TiO2 coatings on the photocatalytic inactivation of Bacillus subtilis spores

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

Río de Janeiro

Encuentro; VI Encuentro sobre Aplicaciones Ambientales de Procesos Avanzados de Oxidación (VI EPOA); 2011

Universidad Federal de Río de Janeiro

Photocatalysis is considered an attractive alternative technology for the decontamination of polluted air and water. The applicability of photocatalysis for the inactivation of contaminating microorganisms in air has been studied in recent years. In the present work, the inactivation rate of spores of Bacillus subtilis employing three different TiO2 coating techniques has been evaluated. The first one uses a suspension of Degussa P25 TiO2. The second technique consists in a sol-gel method that uses titanium tetra-isopropoxide as precursor. The third one is a composite sol-gel/Degussa P25 TiO2 technique. Experiments with one, two and three layers of each coating over glass plates were performed. The coatings obtained with a suspension of Degussa P25 TiO2 showed the best photocatalytic activity for the inactivation of Bacillus subtilis spores, followed by the coatings made with the composite sol-gel/Degussa P25 TiO2 technique. On the contrary, the thin coatings obtained with the sol-gel method rendered the lower kinetic constants. These results confirm the effectiveness of photocatalysis as a disinfection technology for spores inactivation.