Investigation of the photocatalytic activity of various TiO2 nanoparticles in the contaminant remediation

Titanium dioxide (TiO 2 ) has been widely studied due to low cost, availability, and favorable physicochemical properties, making it suitable for a range of applications. In this work, TiO 2 nanoparticle samples were synthesized and evaluated for their photocatalytic degradation of sulfathiazole (STz), bisphenol, and paracetamol as model emerging contaminants. X-ray diffraction analysis revealed anatase and rutile polymorphic phases across the samples. No clear correlation was observed between TiO 2 NPs size and band gap energy likely due to the coexistence of anatase and rutile phases. Photocatalytic efficiency varied according to particle size, polymorphic phase, and preparation method, with degradation times ranging from 105 to 300 min using 100 mg of the catalyst and 10 mg.L −1 concentration of the pollutant solution. Notably, sample P23, despite having a similar particle size to P25, showed lower efficiency in degrading STz due to significant aggregation in aqueous solution, but demonstrated superior activity toward paracetamol and bisphenol. This study highlights that the synthesis method influences particle characteristics and polymorphic phases, which together with state of aggregation and surface chemistry critically affect photocatalytic performance. These findings emphasize the importance of tailoring catalyst design to specific contaminants, as aggregation and surface properties can significantly modulate degradation efficiency beyond size and phase considerations. • Thermal decomposition was effective in forming TiO 2 nanoparticles. • TiO 2 NPs showed high efficiency in degrading emerging contaminants. • Particle size, phases, and surface area are key to photocatalytic activity.