Adsorption and catalytic electro-peroxone degradation of fluconazole by magnetic copper ferrite/carbon nanotubes

Copper ferrite modified carbon nanotubes (CuFe2O4/CNTs) were synthesized and employed as adsorbents/ catalysts to assist electro-peroxone treatment of aqueous emerging pollutant fluconazole (FLC). Results suggest that the synthetic CuFe2O4/CNTs integrated the CNTs adsorption and ferrite magnetic abilities, showing a fast FLC removal and an excellent recyclability. The pseudo-second-order equation and the Langmuir isotherm model could well elaborate the adsorption of FLC on prepared catalysts. Compared to individual processes, electroperoxone treatment exhibited a synergetic degradation of FLC. Approximately 89% FLC transformation was observed in the CuFe2O4/CNTs catalytic electro-peroxone process, 10% higher than that without catalysts, implying that CuFe2O4/CNTs could enhance the peroxone oxidation. Increasing of inlet gasphase ozone concentration (7.2-29.7 mg/L), catalysts dose (0.1-0.8 g/L), initial solution pH (3-11), and reaction temperature (10-30 degrees C) could improve the treatment efficiency, while initial FLC concentration (5-40 mg/L) and natural organic matter contents (humic acid, 0-20 mg/L) have opposite effects. The role of cathodic current density (10-60 mA/cm(2)) was complex, 40 mA/cm(2) was observed as the optimal value. Furthermore, the degradation of FLC followed the hydroxyl radicals (HO center dot) oxidation mechanism. The production of HO center dot was mainly via peroxone reactions, and the presence of CuFe2O4/CNTs could catalytic ozone and H2O2 decomposition, thereby promoting HO center dot generation. Although the magnetic CuFe2O4/CNTs had not shown obvious microelectrode characteristics, it combined adsorption and catalytic peroxone oxidation, may serve as the catalyst for electroperoxone process.