Titanium dioxide particles modified by salicylic acid and arginine and their photocatalytic reaction on oil-water interface

Salicylate acid and arginine-modified TiO₂ particles (TiO₂-SA/Arg) were successfully fabricated by impregnation approach using salicylate acid and arginine grafted onto the surface of nano-TiO₂. The morphology, structure and properties of modified samples were characterized by means of Fourier-transform infrared spectroscope (FT-IR), X-ray photoelectron spectroscope (XPS), thermogravimetry ansysis (TGA), ultraviolet-visible diffuse reflectance spectroscope (UV-Vis DRS), scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), surface contact angle analysis, and particle size distribution analysis. The nitrobenzene adsorption capacity and the ability to be attracted to the oil-water interface of the modified samples were also confirmed. Results revealed that salicylate acid and arginine were modified to TiO₂ surface by chelation and bridging structure, respectively. The modified TiO₂ had better hydrophobicity, dispersion properties and adsorption capacity of nitrobenzene than the unmodified TiO₂. A stable O/W Pickering emulsion was successfully fabricated via the photocatalyst stably adsorbed to oil-water interface. Nitrobenzene in Pickeing emulsion-based photocatalytic reaction system, stabilized by modified photocatalyst, showed a higher removal rate of high concentrations of nitrobenzene than the suspension system.