Cost optimization of the current density for electroxidation wastewater processes

The evaluation of treatment costs is one of the aspects which need more attention for the complete introduction of electrochemical reactors as an attractive alternative in the field of advanced oxidation processes. This paper presents the derivation and application of an expression to determine the optimal current density in order to carry out the direct electroxidation process of two pharmaceutical-compound-containing aqueous solutions (50mgdm^-3) in a parallel plate divided cell using platinized titanium as the anode. The calculi are based on the classical definition of the total cost of electrolyzers, including the electrode service life and completed by one experimental value (obtaining a semi-empirical equation) related to the relationship between the abatement kinetics and the applied current density.The determined value of the optimal current density resulted to be far from the diffusion-limiting current density, consequently, far from the maximum current efficiency, since the experimental parameter includes all other phenomenologies associated with rising in the electrical field across the cell.The methodology could be useful to compare, in terms of cost, different electrochemical reactors and electrode materials for the treatment of a specific organic pollutant.