Journal de la science et de l'ingénierie textiles

Kinetic Study for Reactive Red 84 Photo Degradation Using Iron (III) Oxide Nanoparticles in annular reactor

Abstract

Cano-Guzmán CF, Pérez-Orozco JP, Hernández-Pérez I, González-Reyes L, Garibay-Febles V and Suárez-Parra R

Iron oxide nanoparticles (Fe₂O₃ NPs) were prepared by mixing iron(II) sulfate (FeSO4) and hydrogen peroxide (H₂O₂) in aqueous solution at pH 3. Fe₂O₃ NPs are used to degrade Reactive Red-84 (RR-84) azo dye in a glass annular photo-reactor using a white light lamp. The presence of Fe₂O₃ NPs was verified by HRTEM analyses. Kinetic studies were made varying the reagents concentration and the reaction rate was controlled increasing the concentration of iron ions in comparison with H₂O₂. Langmuir-Hinshelwood (L-H) kinetic model was performed to analyze heterogeneous catalytic reactions under illumination conditions. The elimination process of azo dye followed the pseudo first-order kinetic according to L-H model. The adsorption process of the azo dye on the catalytic surface was determinant for the dye photodecomposition. The linear expression of the Langmuir adsorption isotherm under darkness was further used to establish the maximum amount of dye adsorbed Q_max=0.80 ± 0.18 mg*mg_catalyst^-1 and the adsorption constant k_ads=0.016 ± 0.004 L*mg-1. The Langmuir-Hinshelwood equilibrium constant for dye adsorption under illumination conditions was K_L-H=0.03 ± 0.02 L*mg-1. This similarity with adsorption constants could depict an evidence which suggest that Fe₂O₃ NPs are presents in Fenton´s reaction (FeSO4/H₂O₂) interacting as catalysts in the degradation of organic substrates.