Photocatalytic performance and interaction mechanism of reverse micelle synthesized Cu-TiO2 nanomaterials towards levofloxacin under visible LED light

The degradation performance of Cu-TiO 2 nanomaterials towards levofloxacin (LFX) antibiotic was investigated under an environmentally benign visible LED light source. Cu-TiO 2 nanomaterials were prepared using the reverse micelle sol–gel method with different copper content ranging from 0.25 to 1.0 wt% concerning titania. Characterization of Cu-TiO 2 samples was performed by XRD, TEM, UV–Vis, BET, ICP-MS, FTIR and XPS techniques. 0.5 wt% Cu-TiO 2 showed crystallite size below 6 nm, surface area (69.85 m 2 /g) and significant visible light absorption capacity. Both Cu 1+ and Cu 2+ are formed in lower Cu-doped TiO 2 samples, whereas only Cu 2+ is present in higher Cu-doped TiO 2 samples as evident in XPS analysis. 0.5 wt% Cu-TiO 2 has shown the optimum photocatalytic degradation of 75.5% under 6 h. of a visible light source. FTIR analysis of LFX adsorbed Cu-TiO 2 materials indicated the pollutant–catalyst interaction, where the declining trend was observed in photocatalytic degradation efficiency for higher Cu-doped TiO 2 samples due to copper-LFX complex formation. Copper-LFX complexes are formed due to the presence of Cu 2+ in higher Cu-doped TiO 2 nanomaterials, which might have hindered the photocatalytic activity under visible light. Effects of initial pollutant concentration, catalyst loading and visible light intensity on the degradation of LFX are studied. Photocatalytic degradation pathways of LFX using best performing Cu-TiO 2 material were also proposed based on the LC–MS analysis. Graphical abstract