Abstract
BACKGROUND: The aim of the present work was the preparation of TiO~2~ P‐25 working electrodes on Ti substrates (TiO~2~/Ti), their characterization and the study of their photoelectrocatalytic activity towards the inactivation of E. coli XL‐1blue (E. Coli) colonies, used as model pathogenic bacteria, in a novel batch photoelectrochemical reactor.
RESULTS: After annealing of the TiO~2~/Ti specimens at 500 °C, the surface morphology and crystal structure of the TiO~2~ film electrodes were examined by scanning electronic microscopy (SEM) and X‐ray diffraction (XRD), while from differential capacitance measurements the flat band potential was calculated (V~fb~ = − 0.54 V versus Ag/AgCl). The results of photoelectrocatalytic (PEC) experiments concerning the disinfection of E. coli colonies were compared with those of electrochemical (EC) and photocatalytic (PC) inactivation of the pathogen and showed a significant synergy effect in the case of PEC disinfection, leading, at + 1.0 V vs Ag/AgCl cell voltage, to a 100% increase of the apparent rate constant, k~o~, in comparison with the simple photocatalytic process. Reuse experiments showed that the working electrode retains its effectiveness after, at least, 15 times of reuse.
CONCLUSIONS: The photoelectrocatalytic inactivation of E. coli colonies has been studied under artificial illumination in a novel photoelectrocatalytic reactor. The inactivation of 10^3^ CFU mL^−1^ E. coli colonies followed first‐order kinetics, while parameters such as type of semiconductor and concentration of the microorganisms play an important role affecting the reaction rate constant. Copyright © 2010 Society of Chemical Industry