Photocatalytic Degradation of Estriol Using Iron-Doped TiO2 under High and Low UV Irradiation

Abstract

Iron-doped TiO2 nanoparticles (Fe-TiO2) were synthesized and photocatalitically investigated under high and low fluence values of UV radiation. The Fe-TiO2 physical characterization was performed using X-ray Powder Diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Diffuse Reflectance Spectroscopy (DRS), and X-ray Photoelectron Spectroscopy (XPS). The XPS evidenced that the ferric ion (Fe3+) was in the TiO2 lattice and unintentionally added co-dopants were also present because of the precursors of the synthetic method. The Fe3+ concentration played a key role in the photocatalytic generation of hydroxyl radicals (•OH) and estriol (E3) degradation. Fe-TiO2 accomplished E3 degradation, and it was found that the catalyst with 0.3 at.% content of Fe (0.3 Fe-TiO2) enhanced the photocatalytic activity under low UV irradiation compared with TiO2 without intentionally added Fe (zero-iron TiO2) and Aeroxide® TiO2 P25. Furthermore, the enhanced photocatalytic activity of 0.3 Fe-TiO2 under low UV irradiation may have applications when radiation intensity must be controlled, as in medical applications, or when strong UV absorbing species are present in water.

Characterization of Photoactive Fe-TiO2 Lime Coatings for Building Protection: The Role of Iron Content

“…It is well known that the enhancement of the Fe-doped TiO 2 photocatalytic activity under visible light is due to both the separation of the hole-electron pair and the photogeneration of additional electrons in the TiO 2 conduction band [37]. More specifically, Fe 3+ ions can function as hole and electron scavengers, thus inhibiting the recombination of the photogenerated charge carriers and producing Fe 2+ /Fe 4+ ions [38,39]. The latter ions are unstable compared to Fe 3+ , owing to their half-filled 3d 5 orbital; therefore, they have the tendency to react with the absorbed O 2 or the –OH groups of the neighboring surface Ti 4+ ions, playing an active role in the photocatalytic decomposition of MO [37].…”

“…Moreover, the contribution of the t2g level of the 3d orbital of Fe 3+ to the photocatalytic procedure under visible light is based on the absorption of a photon by the metal ion and the transfer of an electron to the conduction band of TiO 2 [38]. The produced electron and Fe 4+ ions further react with the absorbed O 2 and the hydroxyl group, respectively, thus additionally promoting photocatalysis [38,39]. However, it should be mentioned that the beneficial role of the Fe 3+ ions as hole and electron scavengers can be achieved up to an optimum Fe concentration, beyond which the Fe 3+ ions act as recombination centers, inducing decline of the photocatalytic activity [37,38].…”

Hydroxyl Radical Generation by Recyclable Photocatalytic Fe3O4/ZnO Nanoparticles for Water Disinfection

“…Under dark conditions, samples were kept away from any light source; under UV irradiation, samples were illuminated by an UV 365nm lamp (Cole Parmer, 03402-10, USA; UV-A) of 100 W (UVP, B-100AP), and under white light samples were illuminated by a commercial fluorescent lamp of 15 W (Technolite, F15T8D, 610 lumen, Mexico) with a continuous emission spectrum from 380 to 750 nm. 35 The experimental setup is illustrated in Figure 1B.…”

Recent Advances in Endocrine Disrupting Compounds Degradation through Metal Oxide-Based Nanomaterials

“…High and low UV irradiation conditions were investigated for the degradation of estriol (E3) using iron doped TiO 2 nanoparticles [170]. Interestingly, the presence of ferric ion (Fe 3+ ), unintentionally added because of the precursors of the synthetic method, played a key role in the photocatalytic generation of hydroxyl radicals (•OH) and estriol (E3) degradation.…”