Efficient generation of mixed oxidant disinfectants: parametric study on electrode materials and operating conditions

Abstract

Electrochemical disinfection is an efficient method used for treatment of drinking water. It has great environmental compatibility as compared to conventional disinfection methods. In this study, the effects of the electrode materials and working conditions were investigated. The experimental results show that the type 1 (iridium oxide-coated anode and cathode) electrode system generated a high concentration of free available chlorines (FACs) because iridium has higher electrocatalytic activity than ruthenium. When the applied voltage increases, the acceleration of oxidation reactions in the electrochemical cell resulted in the increased generation of FACs. The solution inflow rate is approximately inversely proportional to the residence time of the salt solution in the electrochemical cell. A long residence time can induce a higher FAC generation. In addition, the production of FACs is increased with the decreasing electrode open ratio (a/A). With a/A > 0 and a lower inflow rate, the FAC concentration tends to approach a maximum value because of by-product generation. The ozone species generated in the electrochemical cell were determined by the maximum voltage. The electrode open ratio affected the ozone generation rate due to the mixing effect of cathode products.