Levofloxacin degradation under visible-LED photo-catalyzing by a novel ternary Fe-ZnO/WO nanocomposite.

As semiconductor photocatalysts showing their efficient redox ability upon illumination, new development of materials to enhance the pollution degradation is gaining popularity, especially on their oxidation ability. In this study, a highly stable ternary Fe-ZnO/WO nanocomposite photocatalyst has been synthesized in order to improve charge transfer of photocatalytic oxidation under 30W LED light (425-470 nm) to efficiency degrade the Levofloxacin (LVF) in the solution. This catalyst was characterized and analyzed by XRD, FE-SEM, HR-TEM, X-ray XPS, UPS, PL, TRPL, LSV, EIS, and Photocurrent. Various important factors for the photodegradation were investigated, including Fe content, initial LVF concentration, catalyst dosage, and solution pH. The optimal conditions were Fe 1.0 wt%, LVF 10 mg L, Fe-ZnO/WO dosage 0.5 g L, and pH 7 for LVF photodegradation up to 96% with a kinetic rate constant of 0.0342 min and were stable in photodegradation efficiency (90%) after five test cycles. In the visible LED light, the activation bandgap was estimated to be 2.75 eV with high electron-hole pair separation and charge transfer from Fe-ZnO to WO that could enhance the generation of active species of OH. Moreover, the more effective charge separation of Fe-ZnO/WO were confirmed by lower PL intensity and longer charge carrier lifetime. Fe-ZnO/WO also demonstrated the excellent electrochemical properties with high photocurrent and small resistance. For the LVF degradation, 3 possible pathways were proposed with 12 intermediate products. This study demonstrated that the synthesized Fe-ZnO/WO could serve as a reliable visible-light responsive photocatalysts with the potential for degrading antibiotics in solution.