Effect of the Hydrodynamic Conditions on the Electrochemical Degradation of Phenol on a BDD Anode

The influence of the hydrodynamics of the system on the extent of the electrochemical degradation of phenol, using a boron doped diamond (BDD) anode was investigated. Two different electrochemical cells were used: a batch stirred cell (A), with a volume of 200 mL and a BDD anode of 17.5 cm 2 , and a batch with recirculation cell (B), with a BDD anode of 70 cm 2 and connected to a tank of 30 L. Assays were performed at different stirring speeds and applied current density of 300 A m -2 , for cell A, and various flow rates, with an imposed current density of 100 A m -2 , for cell B. Chemical oxygen demand (COD) and total organic carbon (TOC) tests were performed to the samples collected throughout the assays, as well as UV-Vis spectrophotometric measurements. For cell A, after 2 h assay, COD removals between 84 and 94% and TOC removals ranging from 54 and 86 % were attained. For the assays run with cell B, during 10 h, COD and TOC removals varied from 27 to 51% and from 23 to 46%, respectively. The influence of the turbulence near the electrode’s surface in the combustion efficiency was also analysed.