Hn. Pham et al., PHOTOCATALYTICALLY-MEDIATED DISINFECTION OF WATER USING TIO2 AS A CATALYST AND SPORE-FORMINGSPORE-FORMING BACILLUS-PUMILUS AS A MODEL, Journal of environmental science and health. Part A: Environmental science and engineering, 30(3), 1995, pp. 627-636
The photocatalytic oxidation process has been evaluated as a basis for
disinfecting large volumes of water. A 95 percent reduction in viabil
ity of B. pumilus spores, suspended with TiO2 in water, was observed a
fter exposing the model organism to ultraviolet (UV) light (lambda 365
nm). Kinetic plots showed that the viability of B. pumilus sports dec
reased exponentially. No reduction in viability occurred if B. pumilus
spores were incubated in the dark (control) or if illumination occurr
ed in the absence of a TiO2 catalyst (TiO2 condition). Intermittent il
lumination reduced viable B. pumilus spores more effectively than cont
inuous exposure to UV. For various TiO2 concentrations suspended in wa
ter from 1 mg/ml to 4 mg/ml, maximum losses of viability were observed
at TiO2 concentrations of 2 mg/ml of water and spore densities > 10(9
) CFU/ml. On the basis of the data presented here, the TiO2-based phot
ocatalytic process shows significant potential as a basis for both sta
tionary and portable water disinfecting devices.