Degradation of Methylene Blue Using Fly Ash as a Heterogeneous Fenton Catalyst

Abstract

Fly ash was used as a heterogeneous Fenton catalyst to degrade methylene blue in aqueous solution. The influence off key operating parameters on the degradation efficiency, including the concentrations of hydrogen peroxide and methylene blue, catalyst dosage, and the initial pH, were studied. The optimal degradation conditions were 2 mmol/L hydrogen peroxide, 4 mg/mL of fly ash, and pH 3. Under these conditions, the degradation efficiency was approximately 93% within 4 h. The degradation of methylene blue by heterogenous Fenton process followed the pseudo-first order kinetics and the activation energy shows that the reaction is thermodynamically feasible. Fly ash demonstrated acceptable reusability after 3 successive cycles. The results in the present study indicated that fly ash is a potent cost-effective catalyst for the degradation of organic dyes in aqueous solution by a heterogeneous Fenton process.