Synthesis of nano-FeS and its application as an effective activator of ozone and peroxydisulfate in the electrochemical process for ofloxacin degradation: A comparative study.

In this work, nanopyrite particles (NP) were synthesized by ball mill method and used as a novel source of Fe in the electro-activation of ozone and peroxydisulfate (PDS) for ofloxacin (OFX) removal. Fourier transform infrared spectroscopy, X-ray powder diffraction, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy analyzes were performed to characterize the as-made NP. Optimal values of operating parameters in NP/PDS and NP/O processes were obtained. The OFX (10 mgL) removal efficiency and molar ratio of OFX: oxidant in NP/PDS and NP/Oprocesses were 92%, 0.1:11 and 89%, 0.1:9, respectively. Although the synergistic effect was observed in both systems, it was more significant in the NP/PDS. The results of free radical tracing showed that HOand SO had the more contribution in NP/O and NP/PDS systems for OFX degradation, respectively. In this way, the OFX removal mechanism was the effective release of Fe from the NP in the electro-activation of O and PDS. Moreover, the effect of electrocoagulation process on OFX removal was negligible. The as-made NP overcame the disadvantages of iron electrode corrosion and iron sludge production in the Fe-based classical electro-activation processes. Overall, the performance of the synthesized NP in the OFX oxidation was very successful in terms of sustainability, Fedistribution, removal efficiency, energy consumption and PDS or O activation.