Oxidation of Phenol by Microbubble-Assisted Microelectrolysis

The degradation of phenol under microelectrolysis was enhanced by O2‐microbubbles. Phenol solution was circled in a microbubble‐assisted microelectrolysis reactor under acid conditions. The degradation rate of phenol reached 65 % within 2 h with O2‐microbubbles, compared to 9.5 % and 4 % with air‐ and N2‐microbubbles due to better dissolution of oxygen with finer microbubbles and at higher dissolution pressure. Higher efficiencies of phenol degradation at lower temperature further confirm the role of dissolved oxygen. In the microbubble‐assisted microelectrolysis system dissolved oxygen, carbon steel pellets, and sulfuric acid are necessary conditions for the oxidation of phenol. The conversion of phenol increases with an increasing amount of carbon steel pellets and/or sulfuric acid. Catechol, hydroquinone, and low‐molecular‐weight carboxylic acids are the major products. Microbubble‐assisted microelectrolysis was successfully applied to degrade phenol under acidic conditions with higher efficiency. The degradation rate reached 65 % within 2 h with O2‐microbubbles. In this system, dissolved oxygen, carbon steel pellets, and sulfuric acid are necessary conditions for the oxidation of phenol. The content of dissolved oxygen directly influences the degradation rate of phenol.