Nitrobenzene degradation in Fenton-like systems using Cu(II) as catalyst. Comparison between Cu(II)- and Fe(III)-based systems

Nitrobenzene (NBE) degradation in Fenton-like systems using copper(II) as catalyst was investigated and compared with the trends observed in iron(III)-based systems. UV-vis spectroscopy, HPLC and TOC measurements were used to characterize the evolution of the reaction mixtures. Kinetic profiles were analyzed under a wide range of experimental conditions in order to assess the effects of the reaction temperature, initial concentrations and working pH. For both Cu(II)-based and Fe(III)-based systems, treatment times decreased with increasing oxidant and catalyst concentrations, but augmented with increasing NBE concentration. However, significant differences were observed for Cu(II)-based systems: higher activation energy above room temperature, broader pH range of activity with an optimal pH of about 6.2, absence of 1,3-dinitrobenzene among the reaction products and important reductions in the TOC levels even in the absence of irradiation.