Abstract
In this work, we report the fabrication of a novel photocatalyst (Bi-doped WO3/CFA nanocomposite) for the photocatalytic degradation of ciprofloxacin (CIP) in wastewater. Bi-doped WO3/CFA nanocomposite was prepared by a hydrothermal deposition of Bi-doped WO3 nanoparticles onto activated CFA. The structural and morphological study of the synthesized materials was characterized using a variety of analytical techniques, which include FTIR spectroscopy, X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM-EDS, TEM), BET surface area analysis, UV-Vis diffuse reflectance spectroscopy (UV-DRS), Zeta potential, and photoluminescence (PL). Short nanorod nanoparticles were successfully synthesized, as well as a combination of the nanorod nanoparticles with spherical activated CFA for the nanocomposite. The results showed that the nanoparticles and the nanocomposite had definite crystallinity. Tauc’s plot was used to calculate the band gap energies of raw CFA (2.46 eV), activated CFA (1.05 eV), Bi-doped WO3 nanoparticles (2.42 eV), and Bi-doped WO3/CFA nanocomposite (2.04 eV). The BET surface area of raw CFA activated CFA, Bi-doped WO3 NPs, and Bi-doped WO3/CFA nanocomposite was found to be 6,279 m²/g, 6,791 m²/g, 50,101 m²/g, and 29,45 m²/g, respectively. Catalyst-free, Bi-doped WO3 NPs, and Bi-doped WO3/CFA nanocomposite were used for the photocatalytic degradation of CIP under visible light for 0-120 min, the nanocomposite showed good degradation of CIP than the catalyst free and NPs, this is because of its low band gap and the stability of the nanocomposite since the nanocomposite is a stable photocatalyst due to the synergy between Bi, WO3, and the activated CFA, it also showed an increased photocatalytic activity due to the dopant (Bi), the binary photocatalyst (WO3/CFA) and a lower band gap. Catalyst loading of 40mg (Bi-doped WO3/CFA nanocomposite) and 5ppm ciprofloxacin were optimized to get the photocatalytic degradation of 70% under visible light irradiation for 0-120 minutes. The application was conducted varying parameters like concentration, dosage and pH, and the results indicated that the optimal conditions for the degradation of CIP (90% after 120 min) were comprised of a catalyst loading of 40 mg, pH of 7 and concentration of 5 ppm.