Visible photocatalytic activity of co-doped TiO2/Zr,N nanoparticles in wastewater treatment of nitrotoluene samples

Abstract

The elements of zirconium and nitrogen were used as doping elements and the sol-gel method was applied for the preparation of nanoparticles of TiO2, TiO2/Zr0.1, TiO2/N0.1 and TiO2/Zr0.05,N0.05. Then, the photocatalytic activity of nanoparticles of undoped and doped TiO2 was studied in the treatment of wastewater samples containing 2,4-dinitrotoluene (2,4-DNT), 2,6- dinitrotoluene (2,6-DNT) and trinitrotoluene (TNT) under the visible light irradiation. During radiation time of 12 h, a treatment efficiency of 35.9, 42.4, 61.5 and 67.2% was obtained in the presence of the photocatalysts of TiO2, TiO2/Zr0.1, TiO2/N0.1 and TiO2/Zr0.05,N0.05, respectively. As it is seen, the co-doped titanium dioxide shows the highest photocatalytic activity in the visible region compared to the other used photocatalysts. The nanoparticles of TiO2/Zr0.05,N0.05 were characterized by field emission – scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), B.E.T. surface analysis and diffuse reflectance spectroscopy (DRS). The XRD patterns did not show any change in the crystalline structure of doped TiO2. The DRS spectra indicated the band-gap energies of 3.17, 2.98, 2.91 and 2.78 eV for TiO2, TiO2/Zr0.1, TiO2/N0.1 and TiO2/Zr0.05,N0.05 nanoparticles, respectively.