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

- Release of NOx during oxidation by OH of N-containing aromatic pollutants.
- Different N-volatile species released depending on N-functional group.
- Differential Electrochemical Mass Spectroscopy to identify N-volatile species.
- Mineralization process demonstrated by CO2 emission detection.

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 NOx species from the oxidation of these pollutants by OH. The evolution of these hazardous NOx during the water treatments by 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 NOx has been ascertained and the overall current efficiency of conversion of N-containing pollutants to CO2 and NOx was 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.

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