Effects of oxidant concentration and temperature on decolorization of azo dye: comparisons of UV/Fenton and UV/Fenton-Iike systems.

This study applies photo-Fenton and photo-Fenton-like systems to decolorize Cl. Reactive Red 2 (RR2). The oxidants were H2O2 and Na2S2O8 Fe2+, Fe3t and CO2+ were used to activate these two oxidants. The effects of oxidant concentration (0.3-2 mmol/L) and temperature (25-55 °C) on decolorization efficiency of the photo-Fenton and photo-Fenton-like systems were determined. The decolorization rate constants (k) of RR2 in the tested systems are consistent with pseudo-first-order kinetics. The rate constant increased as oxidant concentration and temperature increased. Activation energies of RR2 decolorization in the UV/H2O2/Fe2+, UV/H2O2/Fe3t UV/Na2/Fe2+ and UV/ Na+ systems were 32.20, 39.54, 35.54, and 51.75 kj/mol, respectively. [ABSTRACT FROM AUTHOR]