Enhanced degradation of Orange G by permanganate with the employment of iron anode.

Iron anode was employed to enhance the degradation of Orange G (OG) by permanganate (EC/KMnO4). Continuously generated Fe2+ from iron anode facilitated the formation of fresh MnO2, which plays a role in catalyzing permanganate oxidation. The EC/KMnO4 system also showed a better performance to remove OG than Fe2+/KMnO4, indicating the importance of in situ formed fresh MnO2. Besides, the effects of applied current, KMnO4 dosage, solution pH, and natural organics were evaluated and results demonstrated that high current and oxidant dosage are favorable for OG removal. And the application of iron anode has a promoting effect on the KMnO4 oxidation over a wide pH range (5.0-9.0), while the Fe2+/KMnO4 process does not. For natural organics, its presence could inhibit OG removal due to its competitive role. And the promoting effect of OG removal by the EC/KMnO4 process in natural water was confirmed. At last, the EC/KMnO4 process showed a satisfying performance on the decolorization and mineralization of OG. This study provides a potential technology to enhance permanganate oxidation and broadens the knowledge of azo dye removal.