Abstract

GOMEZ-GONZALEZ, Sandra Marcela; RODRIGUEZ-PEREZ, Jonhy Roberto; CASTELLANOS-BLANCO, Nahury Yamile  and  CORTES-HERNANDEZ, Héctor Fabio. Heterogeneous photocatalysis for ortho- and meta-nitroaniline degradation. Rev. acad. colomb. cienc. exact. fis. nat. [online]. 2021, vol.45, n.174, pp.300-312.  Epub Sep 18, 2021. ISSN 0370-3908.  https://doi.org/10.18257/raccefyn.1315.

Nitroanilines are compounds widely used in chemical pesticides, derived from azo dyes, pharmaceutical products, and fuel additives, among others. The study and application of nitroanilines have been important from a commercial and industrial perspective; however, it has been found that the elimination of nitroaniline derivatives in water bodies at low concentrations generates high contamination. In this sense, the study of alternative techniques and processes for their degradation is important. In the present study, we proposed a process for the degradation of ortho- and meta-nitroaniline derivatives using heterogeneous catalysis with TiO2. We created a laboratory-scale prototype reactor and evaluated the amount of TiO2, the pH value, and the concentration of oxidant (H2O2) for both nitroanilines and we were able to determine the degradation kinetics, analyze the catalyst recovery, and establish the optimal degradation conditions. We found that the amount of peroxide and pH value account for the highest percentage of degradation. Finally, we obtained the mineralization of 93.5% and 97.6% for the ortho- and meta-nitroaniline isomers, respectively, with a pseudo-zero-order reaction for the degradation of both compounds based on the Langmuir-Hinshelwood mechanism.

Keywords : 2-nitroaniline; 3-nitroaniline; Photodegradation; TiO₂; Pseudo-zero-order.

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