Effect of operating parameters on decolorization and COD removal of three reactive dyes by Fenton's reagent using fluidized-bed reactor

This investigation evaluates the effectiveness of the fluidized-bed Fenton process in treating Reactive Black 5 (RB5), Reactive Orange 16 (RO16) and Reactive Blue 2 (RB2) dyes in an aqueous medium. The Fe2+ as the catalyst and H2O2 as the oxidizing agent are added to the fluidized-bed reactor. This study also examines how operating conditions, Fenton reagent concentrations, and carriers affect the removal efficiencies of the fluidized-bed Fenton process. Experimental results indicate that excessive hydrogen peroxide had scavenging effects and decreased dye degradation. The [H2O2]:[Fe2+] ratio was a significant operating factor in dye decolorization. Under appropriate conditions, the highest removal rates of 99%, 99% and 96% were for the RB5, RO16 and RB2 colors, respectively. Additionally, chemical oxygen demand (COD) removal efficiencies for RB5, RO16 and RB2 were 34%, 47% and 49%, respectively. Under the same operating conditions 2 mg/L Fe2+, 100 mg/L H2O2 and 74.07 g carrier/L, at pH 3 the removal efficiencies of color and COD had the following order: RO16 > RB5 > RB2.

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► The technology applied in this study uses cheap chemicals, which are non-toxic.
► This investigation evaluated the effectiveness of the fluidized-bed Fenton process in treating three kinds of dyes.
► The color and COD removal rates for these three dyes were >96% and 34–49%, respectively.