Could NO_x be released during mineralization of pollutants containing nitrogen by hydroxyl radical? Ascertaining the release of N-volatile species

Advanced oxidation processes emerged as highly promising water treatment technologies for the abatement of organic pollutants in waters. The treatment of N-containing aromatic pollutants such as amines and nitro-derivatives is of great relevance due to their carcinogenicity. However, one of the major questions is the possible release of NO_xspecies from the oxidation of these pollutants by [rad]OH. The evolution of these hazardous NO_xduring the water treatments by [rad]OH has been suggested to explain the loss of nitrogen during the mass balances, but unfortunately this hypothesis has not been demonstrated experimentally. In this work, the release of NO_xhas been ascertained and the overall current efficiency of conversion of N-containing pollutants to CO₂and NO_xwas estimated semi-quantitatively using differential electrochemistry mass spectroscopy (DEMS) during electrochemical advanced oxidation process with boron-doped diamond (BDD) anodes. Moreover, the relationship between the distributions of N-volatile species with the nitrogenized functional group of each pollutant has been highlighted.