Nano Fe(IO3)3 as a heterogenous catalyst for the photo-Fenton reaction

Abstract

The Fenton reaction is a powerful method of degrading pollutants. The rate of the reaction is improved in an acidic environment, which limits its application. To overcome this drawback, the reaction can be performed under visible light irradiation at a neutral pH. In this condition, a photo-Fenton catalyst is required. For this purpose, Fe(IO3)3 was synthesized by precipitation method. X-ray diffractometry revealed that the prepared product was amorphous and the presence of the Fe-O stretching mode in Fe(IO3)3 was confirmed by Fourier-transform infrared spectroscopy. The X-ray photoelectron spectrum of Fe(IO3)3 showed peaks corresponding to I5+ and Fe3+. Energy-dispersive X-ray spectroscopy confirmed that the Fe-to-I atomic ratio was 1:3. Due to its low bandgap energy, Fe(IO3)3 exhibited photo-Fenton properties when exposed to visible light irradiation. As a result, Fe(IO3)3 could effectively degrade rhodamine B (RhB), reactive orange 16 (RO), and tetracycline hydrochloride (TC). Trapping experiments confirmed that the hydroxyl radical was the dominant oxidizing agent responsible for degrading the three pollutant models. The ability of Fe(IO3)3 to degrade the three pollutant models decreased as the pollutant model concentrations and initial pH values increased. Conversely, the degradation activity of Fe(IO3)3 increased as the catalyst loading was increased. The degradations of all pollutant models were confirmed by mass spectrometry. When the reaction was completed, the parent peaks of the pollutant models were no longer detected, and peaks representing phenolic compounds, sulfonate compounds, and carboxylic acids were observed.