Catalytic Degradation of p-Chlorophenol by N-117 Supported Fe (Ⅱ) Catalyzed Heterogeneous Fenton Reaction

Iron loaded N-117 Nafion membrane has been proved to be an efficient and stable heterogeneous Fenton catalyst. In this paper, Fe(Ⅱ) loaded N-117 was used to catalyze Fenton reaction and p-chlorophenol degradation. The influences of initial pH, hydrogen peroxide concentration, chlorine and humic acid on its catalytic activity and stability were investigated. Fe(Ⅱ) loaded N-117 can effectively catalyze p-chlorophenol degradation, increase the pH range for Fenton reaction, and reduce the inhibition of chloride ion on p-chlorophenol degradation. When initial pH was 9.0, p-chlorophenol degradation rate was 87.3% within 300 min. Catalytic reaction rate decreased as the initial pH was increased. When initial pH was 3.0 and H₂O₂ mass concentration was 100 mg/L, p-chlorophenol degradation rate was 95.6% within 20 min, with dissolved Fe mass concentration being limited to 0.67 mg/L. When H₂O₂ mass concentration exceeded 100 mg/L, the rate of p-chlorophenol catalytic degradation did not go up with H₂O₂ mass concentration and it was limited by ferryl concentration and mass transfer. As chloride mass concentration increased from 0 to 500 mg/L, p-chlorophenol degradation rate remained no less than 87.0% within 60 min reaction time. However, p-chlorophenol degradation rate was decreased, and the dissolution rate of Fe was enhanced. When the mass concentration of humic acid was increased from 0 to 25 mg/L, p-chlorophenol degradation rate remained no less than 90.2% within 60 min. Total dissolution of Fe increased from 0.67 mg/L to 9.4 mg/L, while total amount of Fe dissolution was only 4.7%. Fe clusters were observed on the surface of the used N-117, but the membrane skeleton was not destroyed by oxidation.