Oxidation of TNT by photo-Fenton process

A series of photo-Fenton reactions have been performed for the degradation of 2,4,6-trinitrotoluene (TNT) in a 4.2-l reactor. The degradation reaction rate of TNT followed a pseudo-first-order behavior; and the rate constants for 2.4 mW cm−2 UV only, 2.4 mW cm−2 UV/H2O2, Fenton, photo-Fenton (2.4 mW cm−2) and photo-Fenton (4.7 mW cm−2) were 0.002 min−1, 0.007 min−1, 0.014 min−1, 0.025 min−1 and 0.037 min−1, respectively. Increasing the intensity of UV light, and the concentrations of ferrous ions and hydrogen peroxide promoted the oxidation rate under the experimental conditions in this study. The weighting factor (f), the Fe(II)-promoted efficiency (r) and the promoted-UV light efficiency (p) were calculated to clarify their effects on the TNT oxidation. Moreover, the inhibition effect of hydroxyl radical was also observed in both Fenton and photo-Fenton oxidation when the concentration of Fe(II) were higher than 2.88 mM.