A Ti electrode with a noble metal coating was used for sterilization of water. The main product from electrolysis for sterilization is hypochlorite acid. It was found that the hypochlorite acid production rate was consistently higher on Pt-Ir and Pt-Ir-Ta coated Ti electrodes, compared to Pt coated Ti electrodes. The production rate of hypochlorite was independent of temperature. Therefore, it was thought that this hypochlorite would be effective in sterilization of hot bath water and pool water. At the same time, ozone was generated in the electrolyte water. Generation of ozone was conspicuously observed under electrolysis of Pt electrodes. The production rate of ozone depended on the temperature and the concentration of chloride ions in the electrolyte. A high concentration of ozone was observed when the temperature of the solution was below about 15ºC, concentration of chloride ions was 1mM, and a membrane was used to separate the cell. The ozone generated by electrolysis of Pt coated Ti electrodes had a significant effect on sterilization for Bacillus subtilis spores.
