Effect of electrochemical water treatment processes on carbon steel corrosion in urban water supply system

Electrochemical water treatment processes (EWTPs) are widely applied in the fields of urban and industrial water treatment. However, there are few reports on the corrosion problem of metal caused by the electrolysis process. This study undertook a comprehensive exploration of the long-term corrosion behavior of EWTP on carbon steel (CS) equipment under diverse working voltages and elucidated its corrosion mechanism. This study indicated that the severity of general corrosion, including pitting corrosion and electrochemical corrosion increases proportionally with the elevation of the working voltage. Among these, the most severe pitting corrosion rate has increased by 4.8 times. The primary corrosion mechanism lies in the fact that the ClO- formed through the anodic oxidation of Cl- in EWTP reduces the energy barrier for the corrosion reaction of Fe atoms. The secondary mechanism is that the reduction in the content of CaCO3 in the corrosion products decreases the protective effect, and the decrease in solution pH is conducive to the occurrence of corrosion reactions. This study holds significant guiding implications for the corrosion risk assessment of metal equipment, pipelines, structures in water supply systems that adopt EWTP and the development of relevant corrosion control technologies.