Use of conductive-diamond electrochemical oxidation for wastewater treatment

In this work, the more relevant figures about the use of conductive-diamond electrochemical oxidation (CDEO) in the treatment of industrial wastes are described. It is shown that it is a good technology to treat many industrial effluents with organic loads below 20000 mg dm−3, very efficient, robust and non-selective. It has been observed that the nature of the pollutant does not affect significantly the efficiency of the process. Conversely, organic load and current density show a marked influence in the results. The efficiency of the process increases with the organic content, and mass-transfer limitations seems to be the major drawback of the technology. CDEO is more efficient that electrolysis with other anodic materials, and its main advantage against other advance oxidation technologies is that it does not lead to the formation of oxidation-refractory intermediates. The combined action of direct electrolysis, hydroxyl radicals and that of other oxidants produced from the salts contained in the wastes seems to be the responsible of this good behavior. Two observations related to the production of hydroxyl radicals help to support this: the effect of the pH and that of the anodic potential on the efficiencies of the process.