Inactivation and surface interactions of MS-2 bacteriophage in a TiO2 photoelectrocatalytic reactor

Inactivation of MS-2 bacteriophage in a TiO2 photoelectrocatalytic system was evaluated, wherein TiO2 particles were coated onto an indium tin oxide (ITO) electrode and an electrical potential was applied under black light blue (BLB) irradiation. MS-2 phage inactivation was greatly enhanced by anodic potential, whereas cathodic potential completely inhibited inactivation. Experiments performed with radical scavengers showed that inactivation was primarily caused by hydroxyl radicals, both in the bulk phase and on the TiO2 surface. Application of positive potential to the electrode was found to result in two distinct beneficial effects: (i) electrostatic attraction between the negatively charged viral capsid and catalyst surface, causing improved usage of surface-bound hydroxyl radical, in comparison to conventional TiO2 photocatalytic disinfection; and (ii) higher reactive oxygen species production. Results also suggest that inactivation of various microorganisms including Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Bacillus subtilis spores and Cryptosporidium parvum oocyst was enhanced via positive potential induction to TiO2.

Research highlights
► TiO2 particles were coated onto an ITO electrode in a TiO2 photoelectrocatalytic system.
► Inactivation kinetics of MS-2 phage were greatly enhanced by applying anodic potential to TiO2.
► Electrostatic attraction between the virus and catalyst surface caused improved usage of surface-bound hydroxyl radical.
► Applying positive potential also increased reactive oxygen species production.
► The photoelectrocatalysis system also enhanced inactivation of E. coli, S. aureus, K. pneumoniae, B. subtilis spores and C. parvum oocyst.