Photocatalytic Disinfection of Selected Waterborne Pathogens by Visible Light-Active Nano Iron-Doped TiO Obtained by a Sol-Gel Method.

Bacterial contamination in drinking water systems poses a serious health risk due to poor hygiene, human activities, and cross-contamination within the water supply. This study examines the potential of iron-doped titanium oxide nanometric powder (Fe-TiO) for the photocatalytic disinfection of Gram-negative and Gram-positive under visible light. The Fe-TiO photocatalyst, with an optimal nominal content of 2.5 wt % Fe, was synthesized using a surfactant-assisted sol-gel method, resulting in a mesoporous nanomaterial composed of anatase nanoparticles with a specific surface area of 123 m/g. A sample of undoped anatase TiO obtained using the same sol-gel method and exhibiting a specific surface area of 116 m/g, was utilized to confirm the role of Fe-doping in disinfection. The nanopowders were characterized using X-ray diffraction, N sorption at -196 °C, diffuse reflectance UV-vis spectroscopy, X-ray photoelectron spectroscopy, electrophoretic mobility measurements, high-resolution transmission electron microscopy combined with energy-dispersive X-ray spectroscopy, and field emission scanning electron microscopy. Photocatalytic disinfection tests were conducted using 1 and 0.5 g/L Fe-TiO with varying initial bacterial concentrations, with 1 g/L yielding the most promising results under the experimental conditions employed. After 240 min of treatment with 1 g/L Fe-TiO, a 99.9% removal of both and was achieved starting from a bacterial concentration of 1 × 10 CFU/mL. A 99.9% removal of and a 99.8% removal of were achieved starting from 1 × 10 CFU/mL. The Fe-TiO nanomaterial was effective against high concentrations of both bacteria under visible light. Reusability was studied by recovering the Fe-TiO nanoparticles and assessing their performance over three cycles. The photocatalytic disinfection effectiveness of Fe-TiO nanoparticles under visible light was validated using an actual tap water sample containing 167 CFU/mL and 8 CFU/mL . The bacteria were photocatalytically inactivated within 30 min.