Enhancement of phage inactivation using photocatalytic titanium dioxide particles with different crystalline structures

Abstract

To investigate the effect of crystalline structures on biocidal activity of TiO 2 particles, the photocatalytic deactivation of phage MS2 was conducted using the mixture of anatase- and rutile-type TiO 2 particles under irradiation with a black light lamp. Apparent deactivation rate constant, k′, was determined by applying the first-order kinetics to the time profiles of phage deactivation and the k′ value was found to be maximized at anatase ratio of R an = 70 wt%. Considering the quantity of phage particles adsorbed on TiO 2 surfaces, q T, it was also found that the k′/ q T value at R an = 70 wt% was 4.3 and 5.4 times, respectively, as compared with those at R an = 0 and 100 wt%. The kinetic analysis of phage deactivation supported the consideration that the close contact between both types of TiO 2 particles caused the enhancement of quantum yield and thereby the increased generation of reactive oxygen species in TiO 2 photoreaction.