Enhanced Photocatalytic Activity of Ag-Doped WO3 for Antibiotic and Bacterial Removal in Fishponds

Abstract

A nanocomposite of Ag/WO₃ was synthesized through a two-step process: first, the hydrothermal synthesis of WO₃ using Na₂WO₄, followed by gamma irradiation to dope the material with silver nanoparticles (Ag). To study the effect of silver doping, three different Ag⁺ concentrations −1, 2, and 3 mmol were introduced to a fixed 20 mmol concentration of WO₃. The resulting nanocomposites were designated as AgW1, AgW2, and AgW3, respectively. The presence of Ag was confirmed using elemental mapping, Energy Dispersive Spectroscopy (EDS), and X-ray diffraction (XRD). Dynamic Light Scattering (DLS) measurements revealed particle sizes of 6.879, 7.010, 7.093, and 7.101 μm for WO₃, AgW1, AgW2, and AgW3, respectively. The crystallite sizes of the Ag nanoparticles in the Ag/WO₃ composites, as determined from the XRD patterns, were found to increase with Ag content, measuring 42.5 nm, 53.2 nm, and 56.8 nm for AgW1, AgW2, and AgW3. The band gap energies, determined by UV-Vis Diffuse Reflectance Spectroscopy (DRS), decreased from 2.4 eV for WO₃ to 2.35, 2.30, and 2.25 eV for AgW1, AgW2, and AgW3, respectively. The photocatalytic activity was assessed through chloramphenicol degradation and antibacterial tests against E. ictaluri pathogens in catfish, using the Minimal Inhibitory Concentration (MIC).