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

Abstract

Abstract

Degradation of the azo dye reactive brilliant red K-2BP (K-2BP) by ultrasound radiation combined with zero-valent iron (US-Fe⁰) was studied, and the mechanism of Fe⁰ enhancement for K-2BP degradation was investigated. By determining the of •OH radicals and Fe²⁺ in the US-Fe⁰ system, it was verified that the synergetic effect between sonication and Fe⁰ was mainly due to the increase in •OH radicals concentration resulting from Fenton's reaction. Degradation of K-2BP by the US-Fe⁰ process followed a pseudo-first-order kinetics, and the degradation rate constants were 3.04×10⁻³ min⁻¹ and 3.88×10⁻² min⁻¹ for US alone and US-Fe⁰ process, respectively. Degradation rate of K-2BP increased with increase in Fe⁰ 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-Fe⁰ system.