Effect of solar-like radiation on the autocatalytic degradation of nitrobenzene using Fe+3 and hydrogen peroxide.

LUCIANO CARLOS; DEBORA FABBRI; ALBERTO CAPPARELLI; ALESSANDRA BIANCO PREVOT; EDMONDO PRAMAURO; FERNANDO S. GARCÍA EINSCHLAG

JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY

ELSEVIER SCIENCE SA

Año: 2009 vol. 201 p. 32 - 38

1010-6030

The effect of simulated solar light on nitrobenzene degradation in Fe+3/H2O2 solutions was investigated under different experimental conditions. Consumption profiles of NBE and H2O2 display an autocatalytic kinetic behavior for both dark and photo-assisted degradation experiments. The rates of the initial slow phase that precedes the catalytic phase are significantly enhanced by irradiation, although the effect of simulated solar light on the rates of the fast phase is negligible. The absolute rates of the slow phase increase with the concentrations of Fe+3 and H2O2, whereas the initial rate of the degree of conversion increase decreases with organic matter loading. The reaction progress was characterized by HPLC, GC-MS, IC, TOC and toxicity analyses. The main products detected were: 4-nitrophenol, 3-nitrophenol, 2-nitrophenol, 1,3-dinitrobenzene, phenol, oxalic acid, formic acid, NO2- and NO3-. Product distribution profiles are discussed in connection with TOC and toxicity measurements. The results show that dark treatment is not capable of lowering the organic content nor of reducing the effluent toxicity to acceptable levels. On the other hand, photo-assisted processes induced by simulated solar light can significantly enhance both mineralization and detoxification efficiencies.