Synthesis and Characterization of TiO₂ Nanotubes (TiO₂-NTs) with Ag Silver Nanoparticles (Ag-NPs): Photocatalytic Performance for Wastewater Treatment under Visible Light

Abstract

In this work, we present the influence of the decoration of TiO2 nanotubes (TiO2-NTs) with Ag silver nanoparticles (Ag-NPs) on the photocatalysis of emerging pollutants such as the antibiotic diclofenac sodium. The Ag-NPs were loaded onto the TiO2-NTs by the anodization of metallic titanium foils. Diclofenac sodium is an emerging pollutant target of the pharmaceutical industry because of its negative environmental impact (high toxicity and confirmed carcinogenicity). The obtained Ag-NP/TiO2-NT nanocomposites were characterized by X-ray diffraction (XRD), photoluminescence spectroscopy (PL), scanning electron microscopy (SEM), transmission spectroscopy (TEM), and X-ray photoelectron spectroscopy (XPS). In order to study the photocatalytic behavior of Ag-NPs/TiO2-NTs with visible cold LEDs, the possible photocatalytic mechanism of antibiotic degradation with reactive species (O2°− and OH°) was detailed. Moreover, the Langmuir–Hinshelwood model was used to correlate the experimental results with the optimized catalyst. Likewise, reuse tests showed the chemical stability of the catalyst.

Keywords

• Ag-NPs/TiO₂ nanotubes
• batch reactor
• wastewater treatment
• reactive species
• kinetic modeling