Photocatalysed degradation of cyromazine in aqueous titanium dioxide suspensions: comparison with photolysis

The fate of cyromazine ( N-cyclopropyl-1,3,5-triazine-2,4,6-triamine), an insect growth regulator, has been studied upon irradiation as well as its photocatalytic treatment (advanced oxidation technology). Most of the organic compounds occurring during the photodegradation have been identified by means of liquid chromatography and mass spectrometry coupled techniques (LC–MS). The main photoproducts of the first degradation steps are amide-triazines and melamine. Simultaneously, carboxylic acids, such as acrylic, pyruvic and glycolic acids have been identified by LC–UV. These acids are resulting from the cyclopropyl degradation. The melamine (1,3,5-triazine-2,4,6-triamine) is transformed into cyanuric acid (2,4,6-trihydroxy-1,3,5-triazine) by means of three successive deaminations. This compound remains very stable in aqueous solution.