A kinetic approach to the effect of catalytic systems on the degradation of C.I. Reactive Blue 160

Abstract This paper describes the application of the catalytic systems H2O2 combined with NaOH, UV-light and Fenton-based in order to study their influence on the degradation kinetics of C.I. Reactive Blue 160 (RB160). Several variables were evaluated including temperature, amount of oxidant, effect of initial pH and nature of the catalyst. Under optimal conditions, decolorization efficiencies of 94.8% (30% H2O2/NaOH, 60 °C, 120 min), 77.1% (30% H2O2/UV, 50 °C, 120 min), 93.3% (30% H2O2/NaOH/UV, 50 °C, 120 min) and 95.5% (0.3% H2O2, [Fe2+] = 0.8 mM, 30 °C, 20 min) were obtained. Although the efficiency values were similar for most catalytic systems, the kinetics behavior was very different, furnishing rate constants (kobs) in the range of 11.8–266.0 × 10−3 min−1. This demonstrates that the nature of the catalytic system strongly affects the reaction kinetics. This study also demonstrated the possibility to degrade RB160 without the addition of a catalyst, with an efficiency of 95.7%, kobs = 68.8 × 10−3 min−1 and half-life time (t½) = 10.1 min (30% H2O2, 60 °C, 120 min). These kinetics parameters are comparable to those obtained with the NaOH-catalyzed system (kobs = 72.7 × 10−3 min−1, t½ = 9.5 min).