Effect of the preparation method and metal content on the synthesis of metal modified titanium oxide used for the removal of salicylic acid under UV light.

Titanium dioxide modified with Ag and Fe was synthesized using two preparation methods, characterized and applied to the photocatalytic degradation of salicylic acid in aqueous solution. The modified TiO ₂ samples were prepared by the sol-gel and wet impregnation methods starting from titanium(IV) isopropoxide and using AgNO ₃ and Fe(NO ₃ ) ₃ ·9H ₂ O as precursors of the modifiers, with their content varying between 0 and 5 wt.%. Catalysts characterization was based on powder X-ray diffraction (PXRD), nitrogen physisorption at 77 K, temperature programmed reduction (H ₂ -TPR), chemisorption of NH ₃ at 343 K and X-ray photoelectron spectroscopy (XPS). The photocatalytic degradation of salicylic acid by modified TiO ₂ was investigated under ultraviolet irradiation at 298 K considering various concentrations of the catalyst, between 100 and 1000 mg _catalyst /dm ³ , and of the organic molecule, between 0 and 15 mg/dm ³ . The catalysts most active in the degradation of salicylic acid were those having the highest Fe content.