Photocatalytic degradation of flumequine by N-doped TiO2 catalysts under simulated sunlight

Abstract

Flumequine (FLU) is one of the most used fluoroquinolone antibiotics in intensive aquaculture, however, it has become a typical pollutant in water environment at present due to inappropriate use. Therefore, it is necessary to develop facile techniques for efficient degradation of FLU. In this work, three N-doped TiO2 photocatalysts were synthesized for degradation of FLU. The obtained photocatalysts were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectrum and UV-Vis diffuse reflection spectra (UV-Vis-DRS). The XRD and XPS results from NH4NO3-doped catalyst (TiO2/AN) confirmed that NO3<sup>-</sup> ions were successfully incorporated into the lattice of TiO2. The TiO2/AN sample exhibited higher photocatalytic performance than other N-doped catalysts under simulated sunlight irradiation, and 100% removal efficiency of FLU was achieved after 4 hours of illumination. The photogenerated holes (h<sup>+</sup>) and hydroxyl radicals (<sup>•</sup>OH) are main reactive species involved in the photocatalytic degradation of FLU. Eight intermediates for photocatalytic degradation of FLU were detected and their toxicities to aquatic organisms were predicted. This study might have important implications for further research on the removal of fluoroquinolone antibiotics in wastewater.

Kinetics and mechanisms of flumequine degradation by sulfate radical based AOP in different water samples containing inorganic anions

“… 12 Zeng et al indicated that the TiO 2 /AN sample exhibited high photocatalytic performance under simulated sunlight irradiation, and 100% removal efficiency of FLU was achieved after 4 hours of illumination. 13 Ashrafi et al found that the effective removal of FLU from aqueous solution by laccase from Trametes versicolor , and the removal rate can reach 77.76% under the optimum conditions. 14 Many studies have reported that hydroxyl radical (HO˙, E 0 = 2.5–3.1 V, <1 μs) driven advanced oxidation processes (AOPs) such as photocatalytic and Fenton processes could degrade FLU effectively.…”

Photodegradation of Sulfamethoxypyridazine in UV/Co(II)/Peroxymonosulfate System: Kinetics, Influencing Factors, Degradation Pathways, and Toxicity Assessment

“…An Acquity UPLC BEH C18 column (1.7 μm, 2.1 × 50 mm) was used to accomplish the separation. More detailed experimental parameters were described in our recent research report (Zeng et al, 2021).…”

Studies on Synthesis, Characterization, and Photocatalytic Activity of TiO2 and Cr-Doped TiO2 for the Degradation of p-Chlorophenol

“…However, despite all these benefits, as TiO 2 has a wide band gap (3.2 eV), its photocatalytic efficiency is less in removing pollutants under different light sources. Therefore, to enhance the photocatalytic activity of TiO 2 , researchers employed different processes like metal doping such as Ag, Mn, Cu, V, Mo, Cr, Fe, and Zn − and non-metal doping such as P, C, N, S, − and TiO 2 nanocomposites . Numerous studies have found that doping metal oxides with transition metals can improve the photocatalytic activity, owing to a shift in the absorption region from UV to visible light due to a change in their electronic structure .…”