Photoelectrochemical properties and reactivity of supported titanium NTs for bacterial inactivation and organic pollutant removal

• Published in: Environmental science and pollution research international 2023-01, Vol.30 (4), p.10733-10744
• Main Authors: Trabelsi, Khaled, Abidi, Mabrouk, Hajjaji, Anouar, Tefdini, Rania, Bessais, Brahim, Rtimi, Sami
• Format: Article
• Language: English
• Subjects: Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Light; Microscopy, Electron, Scanning; Nanotubes - chemistry; Research Article; Titanium - chemistry; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 1614-7499; 1614-7499
• DOI: 10.1007/s11356-022-22923-y

In this work, we report on the effect of anodization time on the morphology, optical, and photocatalytic properties of TiO 2 nanotubes (NTs) allowing bacterial inactivation and two organic pollutant degradation under low-intensity solar-simulated light. Scanning electron microscopy (SEM) showed that the length of the TiO 2 NTs increased from 2.8 to 25.8 μm as anodization time was increased from 15 to 300 min at 60 V, respectively. The X-ray diffraction (XRD) patterns showed that all samples crystallize in the anatase phase after annealing at 400 °C for 3 h. Samples anodized for 30 and 60 min exhibit low diffuse reflection at 400 nm, which was attributed to the disorder-induced exciton scattering at the molecular level. The intensity of the photoluminescence (PL) spectra was found to increase as the length of the NTs increases up to a maximum anodization time of 300 min, revealing the contribution of bulk excitonic states. A maximum photoelectric conversion efficiency of 0.55% was obtained at a potential of − 0.5 V vs. Ag/AgCl for TiO 2 NTs anodized for 60 min. The optimized NTs (anodized for 60 min) showed a photocatalytic bacterial inactivation of a magnitude of 6 log within 360 min and a degradation of indole and methylene blue (MB) under low-intensity solar-simulated light (50 mW/cm 2 ). The stability of the prepared catalyst was tested over several cycles.