Experimental study demonstrates efficient solar-assisted degradation of levofloxacin using a TiO2/ZnO/CQD photocatalyst, highlighting a sustainable strategy for wastewater remediation.
Key Points
Develop and evaluate a biomass carbon quantum dot-modified TiO2/ZnO nanocomposite for enhanced photocatalytic degradation of levofloxacin under solar and visible light.
Synthesized TiO2/ZnO/CQD nanocomposites (~112 nm) by dispersing metal oxide nanoparticles with biomass-derived carbon quantum dots in ethanol.
Characterized material properties and charge transfer via TEM, photoluminescence, and electrochemical impedance spectroscopy.
Assessed levofloxacin degradation efficiency across 10 reuse cycles under solar and visible light, identified degradation intermediates via 2D HPLC, LC-MS, and DFT, and evaluated antibacterial toxicity against S. aureus and E. coli.
TiO2/ZnO/CQDs lowered interfacial charge resistance to 2358 Ω (vs. 2689 Ω for TiO2/ZnO) and achieved higher levofloxacin adsorption (k = 5.0788 × 10⁻⁵ mol/g).
Photocatalytic oxidation of levofloxacin reached 78.32% under sunlight (k = 1.30 × 10⁻² mM/s) and 52.06% under visible light (k = 6.00 × 10⁻³ mM/s) with stable performance across 10 cycles.
Toxicity assays showed low inhibition rates against S. aureus (22.7%) and E. coli (21%), confirming the material's non-toxic profile.