Electrochemical incineration of indigo. A comparative study between 2D (plate) and 3D (mesh) BDD anodes fitted into a filter-press reactor.

This paper compares the performance of 2D (plate) and 3D (mesh) boron-doped diamond (BDD) electrodes, fitted into a filter-press reactor, during the electrochemical incineration of indigo textile dye as a model organic compound in chloride medium. The electrolyses were carried out in the FM01-LC reactor at mean fluid velocities between 0.9 ≤ u ≤ 10.4 and 1.2 ≤ u ≤ 13.9 cm s(-1) for the 2D BDD and the 3D BDD electrodes, respectively, at current densities of 5.63 and 15 mA cm(-2). The oxidation of the organic matter was promoted, on the one hand, via the physisorbed hydroxyl radicals (BDD(·OH)) formed from water oxidation at the BDD surface and, on the other hand, via active chlorine formed from the oxidation of chloride ions on BDD. The performance of 2D BDD and 3D BDD electrodes in terms of current efficiency, energy consumption, and charge passage during the treatments is discussed.