Enhancement of Fenton processes at initial circumneutral pH for the degradation of norfloxacin with Fe@Fe<sub>2</sub>O<sub>3</sub> core-shell nanomaterials

<p>The degradation of norfloxacin by Fenton reagent with core-shell Fe@Fe<sub>2</sub>O<sub>3</sub> nanomaterials was studied under neutral conditions in a closed batch system. Norfloxacin was significantly degraded (90%) in the Fenton system with Fe@Fe<sub>2</sub>O<sub>3</sub> in 30 min at the initial pH 7.0, but slightly degraded in Fenton system without Fe@Fe<sub>2</sub>O<sub>3</sub> under the same experimental conditions. The intermediate products were investigated by gas chromatography-mass spectrometry, and the possible Fenton oxidation pathway of norfloxacin in the presence of Fe@Fe<sub>2</sub>O<sub>3</sub> nanowires was proposed. Electron spin resonance spectroscopy was used to identify and characterize the free radicals generated, and the mechanism for norfloxacin degradation was also revealed. Finally, the reusability and the stability of Fe@Fe<sub>2</sub>O<sub>3</sub> nanomaterials were studied using x-ray diffraction and scanning electron microscope, which indicated that Fe@Fe<sub>2</sub>O<sub>3</sub> is a stable catalyst and can be used repetitively in environmental pollution control.</p>