Efficiency and mechanisms of chlorine dioxide generation by electrocatalytical process

Owing to its higher efficiency and better control of disinfection by-products compared with chlorine (Cl2), chlorine dioxide (ClO2) have been widely applied to disinfectation in public water system, cooling system control and wastewater treatment in the past decades. ClO2 of high purity and high concentration can be electrochemically produced using anolyte composed of specific chemical compounds. Electrochemical process has the advantages of simple dosing, ease of operation and onsite continuous production. In this study, different parameters of membrane electrolysis are varied to determine the appropriate conditions for ClO2 generation. Experimental results show that at operation voltage of 12 V, membrane electrolysis using anolyte composed of 2% NaCl and 6% NaClO2 with initial temperature of 30 °C and NaOH catholyte of 0.5% concentration can yield ClO2 of 906.5 mg/L cocentration and 98.4% purity. Moreover, electrolytic reaction accelerates with increase in NaOH catholyte concentration and decrease in initial pH of anolyte. The production rate of ClO2 is also found to be positively correlated with initial temperature of anolyte.