Synthesis of N-F-codoped TiO2/SiO2 nanocomposites as a visible and sunlight response photocatalyst for simultaneous degradation of organic water pollutants and reduction of Cr (VI)

A new N-F-codoped TiO2/SiO2 nanocomposite was prepared by simple sol-gel method, and strongly stabilized on a substrate used in a fabricated photoreactor. The prepared photocatalysts were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, diffuse reflectance UV/Vis, photoluminescence, field emission scanning electron microscope, energy dispersive X-ray, transmission electron microscope, and N-2 adsorption/desorption methods. The effective parameters of pH, flow rate of the incoming current, and the photoreactor tubes angle against sunlight were optimized. The photocatalytic performance of prepared photocatalysts was evaluated by studying the simultaneous removal of a mixture containing three azo dyes and Cr (VI) in the fabricated continuous-flow photoreactor under visible and solar irradiation. The performance of the designed system was also proved under various outdoor climate conditions. Total organic carbon and flame atomic absorption spectroscopy analysis were performed on the treated sample to confirm the decontamination of the model pollutant mixture. It was found that doping N and F in TiO2/SiO2 nanoparticles caused least agglomeration, enhanced activity under visible and solar irradiation, and fully anatase crystalline structure in the as-synthesized nanoparticles.