Photoassisted fenton degradation of nonbiodegradable azo-dye (Reactive Black 5) over a novel supported iron oxide catalyst at neutral pH

Abstract

A novel supported iron oxide, prepared using a fluidized-bed reactor (FBR), was utilized as a catalyst of the heterogeneous photoassisted Fenton degradation of azo-dye Reactive Black 5 (RB5). This catalyst is much cheaper than Nafion-based catalysts, and can markedly accelerate the degradation of RB5 under irradiation by UVA ( λ = 365 nm). The effects of the molar concentration of H 2O 2, the pH of the solution and the catalyst loading on the degradation of RB5 are elucidated. A simplified mechanism of RB5 decomposition that is consistent with the experimental findings for a solution with a pH of up to 7.0 is proposed. About 70% decolorization was measured and 45% of the total organic carbon was eliminated on the surface of the iron oxide at pH 7.0 after 480 min in the presence of 0.055 mM RB5, 5.0 g iron oxide/L, 29.4 mM H 2O 2, under 15 W UVA.