Systematic studies of TiO2-based photocatalysts anti-algal effects on Chlorella vulgaris

In this study, the validity of TiO 2 -based photocatalysts anti-algal effects was examined with Chlorella vulgaris. Cu-modified TiO 2 (without N dopants) showed clear anti-algal effect under white LED light. N-doped TiO 2 (both with and without Cu modification) and Cu-modified TiO 2 (without N dopants) showed clear anti-algal effects when UV light was used together with white LED light. S-doped TiO 2 had no anti-algal effects and even promoted the growth of algae. The degree of the anti-algal effect differed depending on the dopants, surface modifications, and irradiation light. Photocatalysts create several active spices during their photocatalytic processes. Of these, the effects of superoxide radical (O 2 ·− ) and hydrogen peroxide (H 2 O 2 ) on algae growth were examined. Photocatalysts with high anti-algal effect produced hydrogen peroxides effectively, while there was no correlation between productivity of superoxide radical and anti-algal effects. Thus, the ability to produce hydrogen peroxide is a plausible factor for determining the efficiency of the anti-algal effect of a photocatalysts. Graphical Abstract