INVESTIGADORES
CARLOS luciano
artículos
Título:
Nitration of Nitrobenzene in Fenton's Processes
Autor/es:
LUCIANO CARLOS; DANIELA NICHELA; JUAN TRISZCZ; JUAN FELICE; FERNANDO S. GARCÍA EINSCHLAG
Revista:
CHEMOSPHERE
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Amsterdam; Año: 2010 vol. 80 p. 340 - 345
ISSN:
0045-6535
Resumen:
Previous studies of nitrobenzene (NB) degradation by Fenton and photo-Fenton technologies have demonstrated the formation and accumulation of 1,3-dinitrobenzene (1,3-DNB) as a highly toxic reaction intermediate. In the present study, we analyze the conditions that favor 1,3-DNB formation during NB degradation by Fe2+/H2O2, Fe3+/H2O2, UV/Fe3+/H2O2 or UV/H2O2 processes. Nitration yields in Fenton, Fenton-like and photo-Fenton techniques were much higher than those observed in UV/H2O2 systems. Besides, several tests showed that 1,3-DNB formation increases with the initial iron concentration and decreases as the initial H2O2 concentration increases. In order to asses the key species involved in NB nitration mechanism, additional experiments were performed in the presence of NO2- or NO3-. In dark systems, 1,3-DNB yield significantly increased with increasing [NO2-]0, while it was not affected by the presence of NO3-. In contrast, 1,3-DNB yields were higher and more strongly affected by the additive concentration in UV/NO3- systems than in UV/HNO2/NO2- systems. Dark experiments performed at pH 1.5 in excess of HNO2 along with UV/NO3- tests conducted in the presence of 2-propanol show that hydroxyl radicals play an important role in NB nitration since NB molecule does not react with the nitrating agents ONOOH, NO or NO2. The results indicate that, in the experimental domain tested, the prevailing NB nitration pathway involves the reaction between the OH–NB adduct and NO2 radicals.