A Boron-Doped Diamond Anode for the Electrochemical Removal of Parabens in Low-Conductive Solution: From a Conventional Flow Cell to a Solid Polymer Electrolyte System

Solution conductivity plays a fundamental role for the employment of electrochemical advanced oxidation processes (EAOPs) and in the determination of their energy consumption. In this paper, a conventional flow cell based on BDD anode, which requires the addition of supporting electrolyte, is compared with a cell setup based on solid polymer electrolyte (SPE). The new cell configuration avoids the addition of salt to increase solution conductivity. The two systems performance are compared for treatment of different solutions containing methylparaben, ethylparaben and propylparaben. Both systems are able to remove all the three parabens, but the SPE- system provided a better performance, with a maximum COD removal of 91% and energy consumption of 16.25 kWh m-3 while the conventional one remove a maximum of 81% consuming 10.92 kWh m-3. The influence of parameters such as current density, flow conditions and supporting electrolyte concentration was analyzed, and results confirming that SPE-system is a promising system to treat low conductive solutions polluted by parabens.