Effective and continuous degradation of levofloxacin via the graphite felt electrode loaded with Fe3O4

Abstract Electro-Fenton (EF) generally relies on the addition of iron in acidic conditions, which caused an increase in cost and secondary pollution. In this paper, Fe3O4 was in-situ loaded on the surface of the graphite felt (GF) electrode by a moderate solvothermal synthesis method. The modified electrode (Fe3O4/GF) could be used in a wide pH range (acid, and even neutral conditions), and Fe dissolution was not detected under neutral conditions. Compared with the pre-activated graphite felt electrode (aGF), the Fe3O4/GF electrode could directly utilize the generated hydrogen peroxide (H2O2) to obtain more hydroxyl radicals (•OH). The influence of electrolyte types was also investigated, and the results showed unstable or reductive electrolytes were not conducive to the degradation of levofloxacin (LEV). The Fe3O4/GF electrode had good reusability, and could maintain a LEV degradation ratio of over 70% during 6 cycles. The degradation effect of EF with unmodified GF is poor under neutral conditions, but the degradation with the Fe3O4/GF cathode is continuous and has a high total organic carbon (TOC) removal ratio of 81.4% at 6 h. The Fe3O4/GF cathode is conducive to promote the application of EF technology in the field of wastewater treatment, especially under neutral conditions.