Photocatalysis disinfection of Bacillus subtilis spores in water using different media and agitation speeds

Abstract

The photocatalysis disinfections of Bacillus subtilis spores in water using three different media (zeolite, glass bead, and glass slide) were performed in this study. The media were dip- coated with titanium dioxide and irradiated with ultraviolet-A radiation at an intensity of 3.5 mW/ cm2. The titanium dioxide on each medium was controlled at 0.08 g/L of water. The experiments were conducted under the conditions of no agitation, agitation at a speed of 344 rpm, and agitation at a speed of 787 rpm.

The results reveal that glass slide was the best medium for photocatalysis disinfection with the ef ciency of 92-97% in all conditions. Disinfection ef ciencies of zeolite were 80-91%, while those of glass beads were 62-87%. Agitation or speed of agitation did not affect disinfection ef cacy of coated glass slide, but did affect coated zeolite and coated glass bead.