Current status of electrode corrosion passivation and its mitigation strategies in electrocoagulation

Abstract

As an environmentally friendly electrochemical water treatment process, electrocoagulation has received extensive attention in recent years, with the advantages of no additional chemical injection, no secondary pollution, and low sludge generation. During electrocoagulation, the electrode is corroded and then gradually passivated, resulting in low electrocoagulation efficiency, which limits the wide application of electrocoagulation treatment. This review highlights latest detection of electrode corrosion/ passivation and its mitigation strategies as well as future research direction. We describe the method of detecting electrode passivation by electrode surface morphology and electrochemical analysis, reviews the factors affecting the operation of electrocoagulation and electrode passivation, and provides an overview of methods to mitigate passivation, such as changing the current mode, designing new electrodes, introducing Cl^– into the solution and so on. In-depth research and real-time monitoring of electrode passivation, and the synergistic effect of machine learning and passivation mitigation strategies should be considered to overcome the EC development bottleneck and achieve a large-scale application in actual production.