Carbothermal reduction synthesis of zero-valent iron and its application as a persulfate activator for ciprofloxacin degradation

In the present research, zero-valent iron (ZVI) was synthesized by carbothermal reduction method and its formation mechanism was studied. The obtained material ([email protected]) was applied as a persulfate (PS) catalyst for ciprofloxacin degradation. Further, Scanning Electron Microscopy (SEM) of [email protected] has shown that the crystal shape of Fe2O3 changed with the increase in temperature, and also revealed the spherical morphology of ZVI. X-ray Diffraction (XRD) further verified the process of conversion of Fe2O3 to Fe3O4 and then to ZVI. X-ray Photoelectron Spectroscopy (XPS) revealed that the change of iron valence state during the conversion process and the peak area of Fe2+ increased with sintering temperature. The effect of experimental parameters including pH, [email protected] dosage, PS concentration and temperature on ciprofloxacin degradation, were thoroughly investigated. The results illustrated that the [email protected] has excellent catalytic performance and can remove 90.78% of ciprofloxacin within 120 min. Free radical quenching experiments confirmed that the reaction of ciprofloxacin with ∙OH and SO4∙- mainly occurs on the [email protected] surface. Based on the different experiments, it was proposed that degradation mechanism of ciprofloxacin via [email protected] includes three aspects. Thus, it was found that carbothermal synthesis of [email protected] is cost effective and potential technology for ciprofloxacin remediation.