SONOLYTIC ENHANCEMENT OF THE BACTERICIDAL ACTIVITY OF IRRADIATED TITANIUM-DIOXIDE SUSPENSIONS IN WATER

Irradiated TiO2 suspensions in water were used to inactivate Escherich ia coli and Hansenula polymorpha. Two types of batch reactors employin g static and recirculating solutions were used in this study. Sonolysi s using a 20 kHz ultrasonic unit was found to enhance the microorganis m inactivation in all instances, although the enhancement was more mod est for the batch recirculation reactor. These data are interpreted wi thin the framework of four possible mechanisms. The mechanism based on sonolytic creation of . OH appears to provide the most satisfactory e xplanation of the data trends. The present data also implicate . OH as the dominant bactericidal agent in irradiated TiO2 suspensions.