Photocatalysis disinfection of Bacillus subtilis spores in water under sunlight irradiation

Abstract

This study investigated TiO₂ photocatalysis disinfection efficiency on spores of B. subtilis under black light, sunlight and indoor natural daylight with the aid of H₂O₂. It was found that disinfection efficiency from sunlight irradiation (UVA intensity of 5.93-18.2 W/m²) was higher than that from black light irradiation (UVA intensity of 13.5 W/m²) and indoor natural daylight (UVA intensity of 0 W/m²), respectively. A 95.3% spore removal within 1 h occurred when sunlight UVA intensity reached 23.45 W/m² with the assistance of 80 mM H₂O₂. Between 9 am and 4 pm (min-max UVA intensity of 8.49-23.45 W/m²), spore removal did not significantly vary (p>0.05).

Keywords: solar photocatalysis; spore removal; B. subtilis; water disinfection; TiO₂.