Development of a New Process for Phenol In Situ Oxidation Using a Bifunctional Cathode Reactor

Removal of organic and hazardous pollutants from wastewater by electro-Fenton technology is effective and attractive. However, the low productivity of hydrogen peroxide (H2O2) and its narrow pH working range reduce the possibility of its use in industrial processes. An advanced oxidation process is proposed for phenol removal from wastewater in a developed double-layer-cathode trickle-bed electrochemical reactor (TBER). In this technology, a powerful and environmentally benign oxidant, H2O2, is electroproduced by oxygen electrochemical reduction and then employed to oxidize phenol in wastewater. The cathode in the TBER consists of a double layer composed of a carbon black and poly(tetrafluoroethylene) mixture pasted on a stainless steel mesh to form a high-porosity electrode (C-PTFE-SSM). The highest H2O2 concentration of 46.56 mM was found after 50 min of electrolysis in a potassium hydroxide (KOH) electrolyte solution at a constant voltage. The effects of operating parameters such as the applied voltage, electrolyte and gas flow rates, temperatures, and phenol initial concentration on phenol oxidation were systematically optimized. Phenol was successfully oxidized in the developed reactor with a conversion efficiency of 98.65% under the best operating conditions. A kinetic study was also investigated for the proposed oxidation system at different temperatures. The process was designed to be cost-effective because the catalyst used is carbon black and to on-site produce an ecofriendly oxidant H2O2 and simultaneously oxidize phenol. The cathode was also designed to provide an efficient O2 mass transfer and to avoid any expected byproducts in addition to avoiding the use of ferric ions, which are considered to be a dangerous pollutant for water. It was also designed to be scalable and multiuse, which will be our next development reports including the treatment of phenols and organic compounds, the removal of dyes and antibiotics, the oxidation of ethanol and methanol, and the production of ammonia and perchlorate.

Automated summary

An advanced oxidation process using electro-Fenton technology is proposed to remove phenol from wastewater. H2O2 is electroproduced and used to oxidize phenol, resulting in a conversion efficiency of 98.65%. The process is cost-effective, scalable, and multiuse, and has potential applications in various industrial processes.