Photocatalytic inactivation of Clostridium perfringens spores on TiO2 electrodes

Disinfection of drinking water is commonly carried out by chlorination, however research has shown this method to be ineffective against certain protozoan, viral and biofilm forming microorganisms. Furthermore, chlorination can result in the formation of mutagenic disinfection by-products. Semiconductor photocatalysis may be a possible alternative to chlorination for point-of-use drinking water disinfection. In this work TiO2 electrodes were fabricated using electrophoretic immobilisation of commercially available TiO2 powders onto conducting supports, i.e. indium-doped tin oxide-coated glass, titanium metal and titanium alloy. Photocatalytic inactivation of Escherichia coli and Clostridium perfringens spores in water was demonstrated on all immobilised TiO2 films. The rate of photocatalytic inactivation of E. coli was one order of magnitude greater than that of C. perfringens spores. The application of an external electrical bias significantly increased the rate of photocatalytic disinfection of C. perfringens spores. The effect of incident light intensity and initial spore loading were investigated and disinfection kinetics determined as pseudo-first order.