Fenton Oxidation Kinetics of Azo Dye Acid Light Yellow 2G Wastewater by Online Spectrophotometry

Abstract

The online spectrophotometric technique was adopted to monitor the degradation of simulated Acid Light Yellow 2G (ALY 2G) solution with the Fenton oxidation process, and the kinetic process was also discussed. The effects of the initial concentration of H2O2 and Fe2SO4, pH value, and initial dye concentration on the degradation process were studied. The results showed that the ALY 2G can be degraded by Fenton oxidation, and the colour removal rate of Acid Light Yellow 2G was 94.66% after 300 s when the concentration of simulated wastewater was 20 mg/L, the dosage of Fe2+ was 0.1 mmol/L, the dosage of H2O2 was 0.6 mmol/L, and the pH was 3. The degradation process was divided into two stages: the first stage, the degradation rate is very fast; in the second stage, with the extension of reaction time, the increase of decolourization rate decreases. The first stage of the reaction accords with the first-order kinetics, and the reaction rate constant Kap is 0.04824 s-1. The intrinsic reaction rate constant of ALY 2G and hydroxyl in aqueous solution in the Fenton oxidation method is 0.55 × 109 M-1s-1.

Keywords

• online spectrophotometry, fenton oxidation, acid light yellow 2g, reaction kinetics