Catalytic oxidation activation of peroxymonosulfate over Fe-Co bimetallic oxides for flurbiprofen degradation

In this research, FeCo2O4 nanomaterial was successfully synthesized by a typical sol-gel method and conducted as an effective agent for peroxymonosulfate (PMS) activation to eliminate antibiotics flurbiprofen (FLU), a strong nonsteroidal drug. FeCo2O4 nanomaterial was characterized by XRD, TEM, SEM, and XPS. Various characterization results proved that FeCo2O4 held stable spinel structure. The interfering factors including initial pH, PMS concentration, catalyst dosage, inorganic anions, and humic acid on FLU removal were also discussed. The conclusion was that the removal efficiency of FLU reached 98.2% within 120 min after adding FeCo2O4 (0.4 g L-1) and PMS (3 mM). The optimal pH for FLU degradation was the initial pH of 6.5; too acidic or alkaline was not conductive to the degradation. The existence of HA and Cl- restrained the degradation of FLU, and HCO3- promoted the removal, while the influence of NO3- and SO42- could not be considered. The radical scavenging experiment confirmed that (OH)-O-center dot, O-2(center dot-), and SO4 center dot- participated in FLU removal and SO4 center dot- functioned a leading role. FeCo2O4 showed high efficiency for PMS activation in pH range of 3.0 to 10.0. After the fourth cycle operation, the FLU removal rate exceeded 76.9%, and the Co leaching rate was low during the catalytic reaction. This study shows that FeCo2O4 nanomaterial is an efficient and environment-friendly catalyst, which can be applied for PMS activation to remove organic pollutants in water.