Preparation and characterization of photocatalytic Gd-doped TiO2 nanoparticles for water treatment
2019
Ben Chobba, Marwa | Messaoud, Mouna | Weththimuni, Maduka L. | Bouaziz, Jamel | Licchelli, Maurizio | De Leo, Filomena | Urzì, Clara
In recent years, the photocatalytic process by using TiO₂ nanoparticles (NPs) has produced a great interest in wastewater treatment due to its interesting features such as low-cost, environmental compatibility, and especially capacity to eliminate persistent organic compounds as well as microorganisms in water. In the present work, the photocatalytic activity of Gd-doped TiO₂ nanopowders, with different doping amount 0.1, 1, and 5 mol% synthesized by the sol-gel method, was studied under UV/Visible irradiation for water treatment application. The Gd-doped TiO₂ nanoparticles were investigated for their photocatalytic degradation of methylene blue (MB) dye and antibacterial activities against two bacterial strains namely Stenotrophomonas maltophilia (S. maltophilia) and Micrococcus luteus (M. luteus). MB dye was used as a pollutant model to estimate reactive oxygen species (ROS) generation and to correlate killing action of nanoparticles with the generation of ROS. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Raman spectroscopy were used to characterize the as-synthesized nanomaterials. Photocatalytic, as well as antibacterial tests, showed that doping with an appropriate amount of Gd could reduce the radiative recombination process of photogenerated electron-hole pairs in TiO₂ and induce a significant enhancement in photocatalytic and consequently antibacterial activity. The experimental sequence of bactericidal activity and photocatalytic degradation efficiency exhibited by the different gadolinium-doped nanoparticles was the following: 0.1 mol% Gd-doped TiO₂ > 1 mol% Gd-doped TiO₂ > 5 mol% Gd-doped TiO₂ > pure titania.
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