Electrochemical Advanced Oxidation Processes, Formation of Halogenate and Perhalogenate Species: A Critical Review

Advanced oxidation processes (AOPs) are widely used and suggested for environmentally oriented applications. New combinations of single methods are described in literature. An overview about methods is given focusing on innovative papers of the previous years. At the same time, there are an increasing number of indications and evident demonstrations that the occurrence of harmful by-products is possible. Chlorate, bromate, and perchlorate belong to these by-products of inorganic nature. Corresponding cases are considered and discussed. By studying electrochemical advanced oxidation processes (EAOPs) it was found that radical generating electrodes show strong tendencies of chlorate and perchlorate formation in aqueous systems containing chloride ions. Also, bromate and perbromate formation is possible. Therefore, the authors propose these components as new inorganic criterions in environmentally oriented water treatment. A new project is described considering electrochemical drinking water disinfection in close cooperation between researchers, health and water treatment officials and cell producers.