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

Abstract

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.

Recent Advances in Copper-Based Materials for Sustainable Environmental Applications

“…The reaction rate constant of the nanomaterials was 0.0347 min −1 , and the highest degradation efficiency achieved was 93.3%. The results indicate that the nanomaterials were able to adsorb, oxidize, and degrade levofloxacin under visible LED light [49].…”

Mechanisms in the photocatalytic breakdown of persistent pharmaceutical and pesticide molecules over TiO2-based photocatalysts: A review

“…The oxidative degradation of levofloxacin (LFX) was the primary mechanism followed by others such as defluorination, demethylation, decarboxylation, and ring-opening for the degradation of this pollutant. Figure 6 depicts potential LFX degradation pathways employing 0.5CuT material under visible LED illumination [74]. It was discovered that photocatalytic degradation is inversely related to an initial concentration of the LFX pollutant and directly proportional to catalyst concentration and light intensity.…”

“…Using a GC-MS mass spectrometer, the principal by-products of carbofuran's photocatalytic degradation by granular activated carbon-supported titanium dioxide (GAC-TiO 2 ) were discovered to better comprehend the degradation mechanism involved. By comparing with verifiable analytical standards [60], four carbofuran by-products were found, including (1) 2,3,-dihydro-2,2-dimethylbenzofuran-7-ol, (2) Possible degradation of Levofloxacin under visible light with Cu-TiO 2 [74]. Reproduced from [74], with permission from Springer Nature.…”

“…By comparing with verifiable analytical standards [60], four carbofuran by-products were found, including (1) 2,3,-dihydro-2,2-dimethylbenzofuran-7-ol, (2) Possible degradation of Levofloxacin under visible light with Cu-TiO 2 [74]. Reproduced from [74], with permission from Springer Nature. 2,3,-dihydrobenzofuran-7-ylmethylcarbamate, (3) 7-hydroxy-2,2dimethylbenzofuran-3(2 H)-one, and (4) 1,4-benzene-dicarboxaldehyde.…”

Modulation of the Structure of the Conjugated Polymer TMP and the Effect of Its Structure on the Catalytic Performance of TMP–TiO2 under Visible Light: Catalyst Preparation, Performance and Mechanism

“…Among these, titanium dioxide (TiO 2 ) is deemed the best candidate due to its high activity and low cost [ 5 ]. Unfortunately, its catalytic activity is largely hampered by the low light response and quantum efficiency [ 6 ]. Therefore, to address the shortcomings of TiO 2 , various studies have been carried out, such as precious metal deposition, metal ion or nonmetal atom doping, semiconductor compounding, dye sensitization, and conjugated polymer modification [ 7 , 8 , 9 , 10 ].…”