Enhancement of Fenton processes at initial circumneutral pH for the degradation of norfloxacin with Fe@FeS core–shell nanowires

ABSTRACT

The disadvantages of narrow working pH range (2.5–4.0), accumulation of iron sludge and incomplete degradation have hindered the practical application of the traditional homogeneous Fenton technique. In this research, Fe@FeS core–shell nanowires were synthesised and the innovative Fe@FeS/Fe²⁺/H₂O₂ system was adopted for norfloxacin (NOR) degradation at an initial circumneutral pH. More than 95% NOR has been removed in the Fe@FeS/Fe²⁺/H₂O₂ system within 30 min at pH 7. After investigating the concentration change of total iron, Fe²⁺ and H₂O₂ during the degradation process, NOR degradation in the Fe@FeS/Fe²⁺/H₂O₂ system might be attributed to the combined effect of homogeneous Fenton reaction and heterogeneous Fenton process. Besides that, the added Fe@FeS has accelerated Fe³⁺/Fe²⁺ redox cycle with extremely high degree. The generated reactive ^●OH has been identified by electron paramagnetic resonance spectrometer results, possible degradation intermediates have also been proposed according to Gas chromatography-mass spectrometry analysis results. Moreover, Fe@FeS core–shell nanowires showed excellent reusability, it is a promising heterogeneous Fenton catalyst that is applicable for practical application.

GRAPHICAL ABSTRACT

KEYWORDS:

• Norfloxacin
• core–shell structure
• Fe@FeS nanowires
• heterogeneous Fenton
• oxidation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was financially supported by the National Natural Science Foundation of China [Grant No. 51709103], Natural Science Foundation of Hunan Province, China [Grant Nos. 2018JJ3242 and 2021JJ30362], Science and Technology Innovation Leading Plan of High Tech Industry in Hunan Province [Grant No. 2021GK4055], Training Program for Excellent Young Innovators of Changsha [Grant No. kq1802020], Postdoctoral Science Foundation [No. 2018M630901].