Hemin derived iron and nitrogen-doped carbon as a novel heterogeneous electro-Fenton catalyst to efficiently degrade ciprofloxacin

Heterogeneous electro-Fenton (HEF) technology has become a hot topic for degradation of organic pollutants in water. However, it remains a challenge to design effective catalysts for high H2O2 utilization and pollutant degradation. In this work, we explored a novel iron and nitrogen-doped carbon catalyst derived from hemin (Fe-N-C) using KHCO3-MgO as dual-porogen. The results suggested that the KHCO3-MgO dual-porogen could not only improve the porous characteristics of catalyst, but also expose iron sites and change the proportion of nitrogen species. The pollutant degradation results demonstrated that the Fe-N-C-700/HEF system exhibited high ciprofloxacin degradation efficiency of 93.82% within 50 min and mineralization efficiency of 87.87% within 90 min by low energy consumption. Moreover, cycle experiments and metal ions leaching experiments revealed that the catalyst had good stability and recyclability. Electron spin resonance (ESR) test and radical capturing experiment showed that •OH was the dominant active species in this HEF system. In addition, the Fe-N-C-700/HEF system achieved satisfactory performance in the treatment of real water matrix, indicating the possibility for practical application in wastewater purification.