Removal of emulsified oil by monolithic microchannel-carbon cathode via electropolarization-enhanced adsorption-coupled electro-Fenton oxidation

Electrochemistry is a potential technology to remove emulsified oil. However, during electrochemical removal of emulsified oil, oil droplets with negatively charged electromigrate toward the anode, thus accumulating in the anode area and covering the anode surface leading to anodic isolation. In this study, a new idea of electrochemical removal of emulsified oil through electropolarization-coupled oxidation in the cathodic microchannel was proposed. The oil concentration decreased from the initial 275 mg/L to 39.7 mg/L at residence time of 9.25 min and COD removal rate was 85.1 %. The COD removal rate was higher than most of reported metal electrodes. The electropolarization deformation of emulsified oil droplets was observed by a microscope. The contributions of adsorption, electropolarization, and oxidation to emulsified oil removal was 51 %, 29 %, and 20 %, respectively. These results open a new perspective for removal of emulsified oil by microchannel cathode.