Sludge activated carbon-based CoFe2O4-SAC nanocomposites used as heterogeneous catalysts for degrading antibiotic norfloxacin through activating peroxymonosulfate

Abstract

In this study, the sludge activated carbon-based CoFe2O4 (CoFe2O4-SAC) nanocomposites were prepared by a simple hydrothermal method, which were subsequently applied in degrading the antibiotic norfloxacin (NOR) through heterogeneously activating peroxymonosulfate (PMS). Due to its porous structure and more reactive oxygen species (ROS), various characterizations of the CoFe2O4-SAC composite, such as XRD, FTIR, SEM and XPS, showed that the composite had more efficient catalytic activity than CoFe2O4. The application potential of SAC derived sewage sludge as the support enhanced the catalytic activation performance of the CoFe2O4. NOR could almost be fully degraded within 60 min at pH = 5–9 in the CoFe2O4-SAC/PMS system. The degradation efficiency of NOR was impeded by the strong acidic or alkaline environment. The influences of coexisting anions on the catalytic reaction, such as Cl−, HCO3−, and NO3− were also investigated. After five consecutive cycles, CoFe2O4-SAC could still maintain its good catalytic efficiency, with the NOR removal rate of >90%. Additionally, the reaction mechanism was also examined on the basis of radical quenching study and XPS results. Our findings suggested that, sulfate (SO4−) and hydroxyl (OH) radicals had facilitated the degradation of NOR. The oxygen groups linked to the surface of composited were the primary reactive oxygen species, which developed the oxidation degradation of NOR.