Understanding ozone generation in electrochemical cells at mild pHs

• Published in: Electrochimica acta 2021-04, Vol.376, p.138033, Article 138033
• Main Authors: Rodríguez-Peña, M., Pérez, J.A. Barrios, Llanos, J., Saez, C., Barrera-Díaz, C.E., Rodrigo, M.A.
• Format: Article
• Language: English
• Subjects: Decomposition; Electro-ozonator; Electrochemical advanced oxidation process; Electrochemical cells; Mild pHs; Operation mode; Oxidation; Oxidizing agents; Ozone; Regression coefficients
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2021.138033

•Ozone generation can be attained with PEM electrolyzers operating at mild pHs.•Ozone production at mild pHs can be explained from the oxidation of water.•Ozone is destroyed by interaction with predator species produced electrochemically.•Degradation of clopyralid is attained by a cocktail of oxidants, including ozone.•Good fitting of experimental observations to a simple phenomenological model. In this work, the production of ozone at mild pH conditions using a commercial electrochemical PEM cell CONDIAPURE Ⓡ is evaluated, at once a phenomenological model is proposed to understand the basis of the processes that occur inside the cell. At these pH conditions, the production of ozone can be explained from the oxidation of water, while the decomposition of ozone is found to be extremely important to explain the global experimental behavior observed. Not only is this decomposition a chemical but also an electrochemically assisted process which, in turn, can be related to the production of other oxidants in the cell which interact with ozone behaving as predators. The model formulated explains and satisfactorily reproduces the influence of the operation mode, the current intensity applied and presence and destruction of organics, with regression coefficients (r2) ranging from 0.88 to 0.99, helping to understand how the production of ozone should be promoted during electrochemical processes.