Enhanced inactivation of E. coli bacteria using immobilized porous TiO2 photoelectrocatalysis

Immobilized TiO2 nanotube electrodes with high surface areas were grown via electrochemical anodization in aqueous solution containing fluoride ions for photocatalysis applications. The photoelectrochemical properties of the grown immobilized TiO2 film were studied by potentiodynamic measurements (linear sweep voltammetry), in addition to the calculation of the photocurrent response. The nanotube electrode properties were compared to mesoporous TiO2 electrodes grown by anodization in sulfuric acid at high potentials (above the microsparking potential) and to 1 g/l P-25 TiO2 powder. Photocatalyst films were evaluated by high resolution SEM and XRD for surface and crystallographic characterization. Finally, photoelectrocatalytic application of TiO2 was studied via inactivation of E. coli. The use of the high surface area TiO2 nanotubes resulted in a high photocurrent and an extremely rapid E. coli inactivation rate of ∼106 CFU/ml bacteria within 10 min. The immobilized nanotube system is proven to be the most potent electrode for water purification.