Comparison of homogeneous and heterogeneous Fenton processes for the removal of reactive dye Magenta MB from aqueous solution

Abstract

The contamination of water due to dyes coming from different industries is the current problem all over the world and is a demanding environmental issue that needs to be addressed. In this study, the removal of a reactive azo dye called Magenta MB was done by Fenton process using heterogeneous Fe₃O₄ catalyst and homogeneous FeSO₄ catalyst. The homogeneous Fenton system had a removal efficiency of 90.9% under operating conditions of catalyst concentration of 400 mg/L, H₂O₂ dosage of 0.38 M, initial pH of 3 and concentration of Magenta MB of 50 mg/L. The optimum operating condition as per the experimental results for the heterogeneous Fenton system while using Fe₃O₄ catalyst was 600 mg/L of catalyst dosage and 0.26 M of H₂O₂ for 50 mg/L of initial dye concentration at an initial pH of 2 in 60 min. The dye removal efficiency under this condition was 86.8%. An inhibiting effect of salts and ligands on Fenton system was observed and this inhibition effect increases in the following order: Cl⁻ < SO₄²⁻ ∼ EDTA < F⁻ < oxalate. The dye removal efficiency of the recycled magnetite was found to be 76%, which is less than that of newly prepared catalyst. Magenta MB was successfully removed by Fenton processes. Results showed that magnetite was found to be an efficient Fenton catalyst for dye removal.

Keywords:

• Fenton
• Magenta MB
• Magnetite
• Dye removal
• Advanced oxidation process