Production of value-added substances from the electrochemical oxidation of volatile organic compounds in methanol medium

Abstract

In the search for a method that can remove pollutants from gases or enhance the efficiency of the treatment of liquid wastes, electrolysis of water and methanol solutions containing benzene, toluene, and xylene were carried out in this work. Using a filter-press flow electrochemical cell, the efficiency of two different anodes (diamond coatings and mixed metal oxides) were evaluated against the electrochemical oxidation of contaminants in the different solvents mentioned. Results demonstrate that these pollutants can be removed from both types of matrixes and that the nature of the electrode influences greatly on the efficiency. In aqueous medium both electrodes perform similarly but diamond overcomes metal oxide anodes in methanol. In addition to a higher mineralization rate in that case, several highly value-added products are obtained during the process. For instance, anisole, methyl anisole and dimethyl anisole were produced from electrochemical oxidation of benzene, toluene and xylene, respectively, in methanol medium. These results pointing out that a change in the paradigm of the treatment must be made in the next years, going from the destruction of the pollutants to their conversion into highly valuable products at the frame of the circular economy premises.