Synthesis and characterization of BiVO4 nanoparticles and its photocatalytic activity on levofloxacin antibiotics
In this research, BiVO4 photocatalyst was successfully synthesized through a facile chemical precipitation method. The as-synthesized photocatalyst was characterized using X-ray diffraction (XRD), scanning electron microscope accompanied with an energy-dispersive X-ray spectroscopy (SEM/EDS) and UV–Vis diffuse reflectance spectroscopy (UV–Vis/DRS). The photocatalytic activity of the as-synthesized photocatalyst was tested on the degradation of levofloxacin as a model pollutant. 85% degradation of 20 ppm levofloxacin was achieved within 90 min of visible light irradiation as compared with 18% using commercial photocatalyst P25, under the same experimental conditions. Such enhanced activity was attributed to higher absorption of visible light by the as-synthesized BiVO4 that led to formation of a large number of reactive species. The kinetics of the photodegradation process was explained in terms of the Langmuir Hinshelwood model. The values of the kinetic rate constant (k) of the photodegradation were 2.52 x 10-3 min-1,and 22.35 x 10-3 min-1 for commercial P25 and the as-synthesized BiVO4 photocatalysts, respectively. The investigation of the total organic carbon (TOC) indicated high mineralization of levofloxacin was achieved. Finally, the as-synthesized BiVO4 photocatalyst was found to retain its high degradation efficiency even after 5 cycles, indicating its stability for repeated applications.
Keywords: Antibiotics, BiVO4, Levofloxacin, Photocatalyst, Photodegradation