Antibacterial Activity of Visible Light-Activated TiO₂ Thin Films with Low Level of Fe Doping

Abstract

Development of effective antibacterial visible light-activated photocatalytic materials in industries including wastewater treatment and food industry has attracted increasing attention. In this work, Fe-doped TiO2 thin films with different doping levels on a glass substrate were prepared by the sol-gel dip-coating method. The as-prepared films were characterized by Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscope (AFM). Raman spectroscopy and XRD results show the crystalline phase of titanium dioxide was anatase, and the range of the crystal size for the films was 19.24–22.24 nm. XPS results indicate that iron was in the form of Fe3+ in Fe-doped TiO2 films. Regarding the antibacterial properties of TiO2 films, the order of antibacterial activity of TiO2 films was 0.1 at% Fe > 0.5 at% Fe > 1.0 at% TiO2 > bare TiO2 > 2.0 at% Fe > 3.45 at% Fe. 0.1 at% of Fe is the optimum dopant ratio related to antibacterial activity. 0.1 at% Fe-doped TiO2 film is highly efficient in inactivating E. coli under 3 h of visible light irradiation, and it remains efficient even in real dye waste water.

Fe-doped TiO2/Kaolinite as an Antibacterial Photocatalyst under Visible Light Irradiation

“…After visible light irradiated for 120 min, the OD600 value of Fe-TiO2/kaolinite is much lower than TiO2/kaolinite and TiO2, where arise to 0.01 and 0.23, respectively. It may be an indication that the formation of photogenerated electronhole pairs on the surface of Fe-TiO2/kaolinite is easier to occur than TiO2 when absorbing visible light because it has a smaller band gap as a result of the mixing of the Fe 2p with Ti 2p orbitals [16][17][18]. These results are consistent with the absorption spectra.…”

“…The absorption peak at 602 cm −1 and 786 cm −1 observed on the spectrum of TiO2 corresponded to the stretching vibrations of Ti−O−Ti [15,16,26,27]. It has been observed that the addition of Fe into TiO2 matrix cause a shift of this band position to 586 cm −1 and 774 cm −1 for the Fe-doped TiO2, it is considered as a sign of existence structure defect [27].…”

“…Many articles describing the fabrication of kaolinite/TiO2 nanocomposites and perform a photocatalytic activity as an anti-bacterial has been published [10, 15,16], wherever its photocatalytic activities as antibacterial were not clearly. Therefore, the aim of this study was to prepare and to characterize the Fe-doped TiO2/kaolinite composite and evaluate its antibacterial activity for Escherichia coli under visible light irradiation.…”

Preparation and Characterisation of Poly(methyl metacrylate)-Titanium Dioxide Nanocomposites for Denture Bases

“…The photocatalytic properties of titanium oxide are well known and broadly described; in presence of water and a close range of UV light (λ ≤ 387 nm) it generates reactive forms of oxygen preventing the development of pathogens and the formation of biofilm [ 31 ]. Meng et al [ 32 ] highlight at the same time that the antibacterial action may be intensified by the modification of TiO 2 itself with such metals as Fe, thus increasing the activating spectrum to the visible light range. The effectiveness of the antimicrobial action is correlated by the authors with the weight content of titanium oxide in relation to PMMA [ 32 ].…”

“…Meng et al [ 32 ] highlight at the same time that the antibacterial action may be intensified by the modification of TiO 2 itself with such metals as Fe, thus increasing the activating spectrum to the visible light range. The effectiveness of the antimicrobial action is correlated by the authors with the weight content of titanium oxide in relation to PMMA [ 32 ]. Cheng [ 33 ] provides the weight content of 5% as optimum in terms of microbiology.…”