Study on the efficiency of FeS₂@NCNT cathode electroactivation of peroxymonosulfate for the degradation of norfloxacin

The advanced oxidation technology based on peroxymonosulfate (PMS) activation offers unique advantages in degrading emerging pollutants. In this experiment, iron disulfide (FeS₂) was encapsulated on nitrogen-doped carbon nanotubes (NCNT) to prepare FeS₂-modified nitrogen-doped carbon nanotubes (FeS₂@NCNT). Using norfloxacin (NOR) as the target pollutant, a study was conducted on the mechanism and performance of FeS₂@NCNT in electro-activating PMS for NOR degradation. The main research includes the following: characterization and electrochemical performance tests of the material revealed that FeS₂@NCNT exhibits excellent electrocatalytic activity and low impedance, with favorable charge storage capacity and electron transfer ability. In the FeS₂@NCNT/PMS system, the effect of various parameters on NOR removal efficiency was examined, and the optimal conditions were determined to be a current density of 15 mA/cm², pH of 6.0, and PMS concentration of 3 mmol/L. Under these conditions, NOR removal reached 93.0% within 60 minutes. Radical quenching experiments indicated that singlet oxygen (¹O₂) is the primary reactive species for NOR degradation, while superoxide radicals (O₂^•⁻), hydroxyl radicals (•OH), and sulfate radicals (SO₄^•-) also contribute to some extent. Additionally, the study explored the impact of coexisting anions on system performance and confirmed that FeS₂@NCNT maintained good catalytic activity after multiple cycles, highlighting the application potential of this composite material in water treatment.