Removal of organic micropollutants from drinking water by a novel electro-Fenton filter: Pilot-scale studies

To assess the performance of a novel 'filter'-type electro-Fenton (EF) device, results are reported from pilot-scale studies of continuous water treatment, to degrade diclofenac (DCF), a typical organic micro pollutant, with no addition of oxidants. The novel 'filter' consisted of three pairs of anode/cathode electrodes made of carbon felt, with cathodes impregnated with iron nanoparticles (gamma-Fe2O3/F3O4 oxides). The best 'filter' performance was obtained at applied potential of 2 V and low water superficial velocities (similar to 0.09 cm/s), i.e., the mineralization current efficiency (MCE) was >20%, during continuous steady state treatment of tap water with low DCF concentrations (16 mu g/L). The EF 'filter' exhibited satisfactory stability regarding both electrode integrity (no iron leaching) and removal efficiency, even after multiple filtration/oxidation treatment cycles, achieving (under steady conditions) DCF and TOC removal 85% and 36%, respectively. This performance is considered satisfactory because the EF process took place under rather unfavorable conditions, such as neutral pH, low dissolved O-2 concentration, low electrical conductivity, and presence of natural organic matter and inorganic ions in tap water. Ongoing R&D is aimed at 'filter' development and optimization for practical applications. (C) 2016 Elsevier Ltd. All rights reserved.