Electrochemical oxidation of ethylenediaminetetraacetic acid (EDTA) on BDD electrodes: Application to wastewater treatment

The electrochemical oxidation of ethylenediaminetetraacetic acid (EDTA) was investigated at boron-doped diamond (BDD) electrodes. Cyclic voltammetry in the potential region of water stability showed that EDTA is oxidised in an irreversible two-electron-transfer mechanism. No fouling phenomena were noticed on the electrode surface. At high anode potential, an oxidation mechanism of EDTA involving hydroxyl radicals, formed during water discharge, was proposed. Moreover, the model previously developed for organic oxidation at nonactive anodes was successfully used in order to predict the trends of chemical oxygen demand (COD) and instantaneous current efficiency (ICE) during EDTA oxidation on BDD electrodes. Bulk electrolyses were performed under different regimes. The very good fit between the experimental results and theoretical values confirmed that EDTA oxidation at the BDD electrode in the potential region of electrolyte decomposition was a fast reaction.