Abstract:
Electrochemical Advanced Oxidation Processes (EAOPs) are emerging technologies to face environmental impact of persistent organic pollutants. These water processes are based on the in situ generation of hydroxyl radical (●OH) capable of completely oxidizing organics. Anodic oxidation with non-active anodic materials such as metal oxides or boron-doped diamond is the electrochemical process most explored, but electro-Fenton technologies can present improved treatment performances in acidic effluents using carbonaceous air-diffusion cathodes. Recently, photoelectrocatalysis emerged as an alternative sustainable approach for environmental remediation. These electrochemical technologies have demonstrated their promising capability to remove persistent organic pollutants. Unfortunately, their scaling-up have been barely addressed.
Herein, we will briefly discuss the fundamentals of different EAOPs in a comprehensive, comparative and systematic manner emphasizing performance and applicability on the removal of persistent organic pollutants. The evolution of dissolved organic carbon, aromatic intermediates, generated carboxylic acids and released inorganic ions, as well as pollutants decay have been considered to ascertain the degradation rate and mineralization degree achieved for each process. Afterwards, scaling-up and reactors design will be addressed. Special emphasis will be driven towards the combination of electrochemical reactors with photochemical reactors to improve treatment performance. Influence of operational variables on treatment performance, mineralization current efficiency, electrical energy per order and operational cost will be discussed. Furthermore, the possible coupling of renewable energies will be presented.