Degradation of Fluoroquinolone-Based Pollutants and Bacterial Inactivation by Visible-Light-Active Aluminum-Doped TiO₂ Nanoflakes

Abstract

The development of a visible-light-active photocatalyst for the removal of organic contaminants from water is of primary importance. In this work, we have developed a one-pot synthesis method for visible-light-active aluminum-doped titania (TiO2) with highly efficient sorption degradation of the fluoroquinolone-based pharmaceutical pollutant norfloxacin in aqueous solution. Here, we reduced the effective band gap of TiO2 by in situ doping of aluminum (1 mol %), which significantly improves the porosity, resulting in a high sorption capacity (209 mg/g) toward norfloxacin. The doping of aluminum in TiO2 makes it photocatalytically active in visible light and overcomes the shortcomings of undoped TiO2 in favor of the photodegradation process. 1% aluminum-doped TiO2 (AT) nanoflakes achieves 93% norfloxacin removal (of 2 × 10–4 M) in 2 h with almost 5 times higher rate constants (0.0143 min–1) compared to undoped TiO2 nanoflakes under visible light. Additionally, a high bacterial disinfection activity of doped samples compared to undoped TiO2 in visible light (nearly 80%) as well as in the dark (nearly 20%) was also observed toward both Staphylococcus aureus and Escherichia coli bacteria. The end product of the degradation process was analyzed using mass spectroscopy to determine the mechanistic pathways of the degradation process and the fate of the pollutants. The reusability of the prepared samples was tested and found to be active even after several cycles.

Effect of ferroelectric polarization on piezo/photocatalysis in Ag nanoparticles loaded 0.5(Ba0.7Ca0.3)TiO3–0.5Ba(Zr0.1Ti0.9)O3 composites towards the degradation of organic pollutants

“…The peak with the binding energy of 530.01 eV corresponds to the lattice O originating from the material. The other peak situated on higher binding energy at 532.50 eV results from the adsorbed O species from the environment shown in Figure 2F 33 . For Ag, signature peaks at 368.43 and 474.38 eV correspond to Ag 3d 5/2 and Ag 3d 3/2 spin‐orbital state.…”

“…The other peak situated on higher binding energy at 532.50 eV results from the adsorbed O species from the environment shown in Figure 2F. 33 For Ag, signature peaks at 368.43 and 474.38 eV correspond to Ag 3d 5/2 and Ag 3d 3/2 spin-orbital state. These peaks indicate the presence of a metallic form of Ag, as shown in Figure 2G.…”

Preparation and Performance Study of Antibacterial Materials Based on GO−TiO2

“…Photo-generated electrons and holes that can potentially help to produce active oxygen and kill bacteria. [8][9][10] In the absence of light, it was found that TiO 2 can alter the bacterial cell wall morphology and permeability, thereby regulate the osmotic balance of bacteria. [6,[11][12][13] Among the carbon-based nanomaterial with antimicrobial properties, graphene oxide (GO) has received extensive attention due to its unique physical and chemical properties.…”

“…So far, antibacterial properties of TiO 2 can be attributed to its excellent photoactivation properties. Photo‐generated electrons and holes that can potentially help to produce active oxygen and kill bacteria [8–10] . In the absence of light, it was found that TiO 2 can alter the bacterial cell wall morphology and permeability, thereby regulate the osmotic balance of bacteria [6,11–13] …”

Progress on the nanoscale spherical TiO2 photocatalysts: Mechanisms, synthesis and degradation applications

“…Since the discovery of photoelectrochemical splitting of water on TiO 2 in 1972, [ 18 ] after decades of research, researchers have been able to prepare a variety of TiO 2 with different morphologies, including nanospheres, [ 19–21 ] nanowires, [ 22 ] nanotubes, [ 23 ] nanosheets [ 24 ] and nanofibers, [ 25 ] and so on. The nanoscale spherical TiO 2 (Degussa P25) is the only commercial mass‐produced morphology with good degradation properties.…”