Electrochemical Disinfection Using Palladium-Coated Carbon Cloth Electrodes II. Electrochemical Disinfection Using a Solar Battery

Abstract

The possibility using a solar battery as a power source for the electrochemical disinfection of microorganisms was examined. A single solar battery with an open circuit voltage 20 V and a capacity of 1 A was used for laboratory scale-examination. The electrochemical disinfection cell containing palladium-coated carbon cloth electrodes was reported previously and a dominant parameter on the disinfection was found to be the concentration of chloride ions. The concentration of NaCl as a source of chloride ions was varied from 0.154 mol dm−3 (saline solution) to 0.00154 mol dm−3 (the concentration being four to ten times that of NaCl in tap water in Tokyo) in this study. Disinfection was examined in only one flow-passage of the microorganisms’ suspension across the electrolytic cell. Escherichia coli was selected as a model microorganism. Disinfection under a clear sky was complete, and was almost complete even under an obscured sky. The viability of E. coli at a current of 100 mA was less than 1×10−6 irrespective of the concentration of NaCl. The viability of E. coli at a current of 50 mA increased to 0.001 in the suspension containing 0.00154 mol dm−3 of NaCl.