Mechanistic Study of the Degradation of Azo Dye Reactive Brilliant Red K-2BP by Ultrasound Radiation and Zero-Valent Iron

Degradation of the azo dye reactive brilliant red K-2BP (K-2BP) by ultrasound radiation combined with zero-valent iron (US-Fe-0) was studied, and the mechanism of Fe-0 enhancement for K-2BP degradation was investigated. By determining the of center dot OH radicals and Fe2+ in the US-Fe-0 system, it was verified that the synergetic effect between sonication and Fe-0 was mainly due to the increase in center dot OH radicals concentration resulting from Fenton's reaction. Degradation of K-2BP by the US-Fe-0 process followed a pseudo-first-order kinetics, and the degradation rate constants were 3.04 x 10(-3) min(-1) and 3.88 x 10(-2) min(-1) for US alone and US-Fe-0 process, respectively. Degradation rate of K-2BP increased with increase in Fe-0 dosage and decreased with increase in the medium pH, reaction temperature, and dye initial concentration. The UV-Vis spectra of K-2BP at different sonication times showed that both azo and aromatic groups were destroyed during degradation in the US-Fe-0 system.