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The electrochemical oxidation of a synthetic wastewater containing Acid Yellow 1 on boron-doped diamond was investigated. The influence of applied current (0.5–3 A), dye concentration (1–3 g L−1), temperature (25–40 °C) and flow-rate (75–300 L h−1) on colour removal and current efficiency was evaluated. It was demonstrated that the complete decolourization and COD removal were achieved in any experimental conditions indicating that the electrochemical oxidation on BDD electrodes is a suitable method for treatment of wastewaters polluted with synthetic dyes. In particular it was found that the decay of Acid Yellow 1 follows a pseudo-first-order kinetic and the oxidation rate was favoured by increasing current and flow-rate, while it was almost unaffected by solution temperature.

Electrolysis in aqueous 1 M HClO4 and 1 M H2SO4 solutions has been carried out under galvanostatic conditions using boron-doped diamond electrodes (BDD). Analyses of the oxidation products have shown that in 1 M HClO4 the main reaction is oxygen evolution, while in H2SO4 the main reaction is the formation of H2S2O8. In both electrolytes small amounts of O3 and H2O2 are formed. Finally, a simplified mechanism involving hydroxyl radicals formed by water discharge has been proposed for water oxidation on boron-doped diamond anodes.