Application of the Magnetic Fraction of Fly Ash as a Low-Cost Heterogeneous Fenton Catalyst for Degrading Ethidium Bromide

Ethidium bromide, which is commonly applied in molecular biological applications, is a mutagenic agent demanding proper treatment. In the present study, the magnetic fraction of fly ash, prepared from the ASTM class F material, was used as a catalyst for a heterogeneous Fenton process for degrading ethidium bromide in aqueous solution. The dosage of the catalyst, the initial pH of the solution, and the initial concentration of hydrogen peroxide significantly influenced the ethidium bromide removal rate. Under optimum conditions (2 mmol/L hydrogen peroxide and 100 g/L of the magnetic fraction of fly ash at pH 3), an ethidium bromide degradation efficiency of 98% was obtained within 4 h. The magnetic fraction of fly ash retained over 95% of its maximal ethidium bromide removal ability after three successive cycles. The heterogeneous Fenton process using the magnetic fraction of fly ash as a catalyst is robust and reusable. Therefore, the approach developed in this study may be an alternative cost-efficient heterogeneous Fenton catalyst for the removal of ethidium bromide from aqueous solution.