Heterogeneous Fenton-like catalysis of Fe-MOF derived magnetic carbon nanocomposites for degradation of 4-nitrophenol

Abstract

Magnetic carbon nanocomposites (Fe–C_x) as heterogeneous Fenton-like catalysts were synthesized by the pyrolysis of iron based metal-organic frameworks (Fe-MOF), and the degradation removal of 4-nitrophenol (4-NP) in aqueous solution was used to evaluate the catalytic activity of Fe–C_x. The results showed that 4-NP could be effectively degraded by Fe–C_x in the presence of hydrogen peroxide. Pyrolysis temperature significantly affected the component, structures and performances of the catalysts, and the as-prepared Fe–C₅₀₀ exhibited the best catalytic performance. Furthermore, the effects of several reaction conditions, such as catalyst loading, H₂O₂ dosage, reaction temperature, and initial pH, on the catalytic degradation of 4-NP were extensively analyzed for the practical applications of Fe–C₅₀₀. At an initial circumneutral pH of 6.21, 89.0% of 0.36 mM 250 mL of 4-NP solution could be degradated after 75 min by the heterogeneous Fenton-like oxidation on the 0.08 g L⁻¹ of Fe–C₅₀₀ in the presence of 7.8 mM H₂O₂. The results of activation energy and the reaction kinetics showed Fe–C₅₀₀ possessed a high catalytic activity in the heterogeneous Fenton reaction of 4-NP. Moreover, the prepared Fe–C₅₀₀ could be reused by an external magnet, and still retained good catalytic activity with 52.4% degradation of 4-NP at the fourth cycle.