Performance of electro-Fenton process for phenol removal using Iron electrodes and activated carbon

Abstract

The objective of the present study was to investigate the efficacy of electro-Fenton (EF) oxidation process for the removal of phenol from synthetic wastewater (initial phenol concentration = 250 mg/L) under varying reaction conditions using iron electrodes. The lab scale EF runs were performed in a 1 L beaker placed on magnetic stirrer assembly. Maximum COD and TOC removals of ∼84% and ∼52%, respectively, were obtained within 30 min reaction at the following operating conditions: stoichiometric amount of H2O2 = 37.2 mM, pH = 5.2 (unadjusted), electrical conductivity = 125 μS/cm (adjusted using NaCl), stirring speed = 100 rpm, current density = 0.8 mA/cm2 and inter-electrode gap = 4 cm. At the above condition, complete phenol removal was obtained within 5 min. The effect of activated carbon (AC) as co-catalyst on the performance of EF process was also studied at the above reaction condition. With AC assisted EF process, TOC removal was increased to 75% from 52.2% (in EF). The enhanced degradation was due to the combined effect of adsorption and oxidation reactions. During modified EF, ferrous iron recycling was also higher compared to that observed during conventional EF process.