Electrochemical Degradation of Reactive Blue 19 Dye by Combining Boron‐Doped Diamond and Reticulated Vitreous Carbon Electrodes

Abstract

Reactive Blue 19 (RB‐19) dye has a low fixation efficiency, a long half‐life and high toxicity. It is easily loss during the cleaning of textiles and can remain in the environment for a long time, causing serious environmental problems if not removed. This study reports the degradation of RB‐19 by: 1) direct electrochemical degradation with boron‐doped diamond (BDD) electrodes and 2) combined processes using BDD and reticulated vitreous carbon (RVC) electrodes that generate H2O2. The direct degradation uses different current densities and concentrations. High currents densities, longer electrolysis times and low volumetric flow rates favour RB‐19 degradation, removing total colour and 100 % TOC after 5 and 60 min, respectively. At a current density of 41 mA cm−2 and a volumetric flow rate of 20 dm3 h−1, the energy consumption to degrade 20 mg dm−3 of RB‐19 was 279 kWh kg−1. The TOC removal of RB‐19 dye combining BDD and RVC at a current density of 41 mA cm−2 was below 72 % after 90 min and the energy consumption increased to 612 kWh kg−1. The higher energy consumption observed during the combined process suggests that the direct degradation process at low volumetric flow rates is more efficient than the combined process.

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