Comparative studies of the Fe 3+/2+–UV, H 2O 2–UV, TiO 2–UV/vis systems for the decolorization of a textile dye X-3B in water

Abstract

The degradation of a common textile dye, Reactive-brilliant red X-3B, by several advanced oxidation technologies was studied in an air-saturated aqueous solution. The dye was resistant to the UV illumination (wavelength λ ⩾ 320 nm), but was decolorized when one of Fe 3+, H 2O 2 and TiO 2 components was present. The decolorization rate was observed to be quite different for each system, and the relative order evaluated under comparable conditions followed the order of Fe 2+–H 2O 2–UV ⩾ Fe 2+–H 2O 2 > Fe 3+–H 2O 2–UV > Fe 3+–H 2O 2 > Fe 3+–TiO 2–UV > TiO 2–UV > Fe 3+–UV > TiO 2–visible light ( λ ⩾ 450 nm) > H 2O 2–UV > Fe 2+–UV. The mechanism for each process is discussed, and linked together for understanding the observed differences in reactivity.