phenol removal from wastewaters by electrochemical oxidation using boron doped diamond (bdd) and ti/ti0.7ru0.3o2 dsa® electrodes

Industrial wastewater containing non-biodegradable organic pollutants consists of highly toxic effluents whose treatment is necessary due to environmental and economical restrictions. In order to treat these effluents, an electrochemical process using a dimensionally stable anode (DSA®) and boron-doped diamond (BDD) electrode was studied. The performance of these electrodes for COD removal from aqueous phenol solution was evaluated in the absence and presence of different chloride concentrations. The results showed that DSA®could be successfully used to remove COD when high chloride concentration (3035 mg L-1 Cl-) and mild current density are employed (50 mA cm-2). On the other hand, the presence of chloride did not have the same significant effect on the COD depletion rate using BDD; however, under mild conditions (50 mA cm-2, 0.190 m s-1), the addition of 607 mg L-1 Cl- improved the COD removal by approximately 52% after 8 hours of electrolysis. The effect of current density (i) and flow velocity (v) were also studied, and it was verified that they have an important role on the process performance, especially when DSA® is used.