| Sol-gel method was used to synthesize pure and metal-doped TiO2 nanoparticles. The optimum experimental conditions for synthesis of pure nanocrystalline TiO2 were found by Analysis of Variance (ANOVA). These experimental parameters include the amount of water, type of acid, acid concentration and ultrasonication duration. Three transition metals including tungsten, vanadium and iron were selected for doping of titanium dioxide at the optimum conditions.;All types of catalysts were characterized by Scanning Electron Microscopy (SEM), which has shown spherical shape of particles for the samples obtained at the optimum conditions. the average diameter of these particles was found to be ranging from 6-14 nm as measured by Particle Size Analyzer (PSA). X-Ray Diffraction (XRD) analysis was carried out in order to investigate the phase of catalysts, which was found to be mainly anatase for all samples calcined at 450°C. The percentage of metals doped on titanium dioxide was measured by Elementary Dispersive Spectroscopy (EDS), which is found to be 2.7%, 1.8% and 1% for tungsten, vanadium and iron, respectively, and the effect of incorporating these transition metals onto titanium dioxide was resulted in the significant increasing of the surface are as measured by (BET).;The photocatalytic activities of these catalysts were investigated by measuring the degradation of methylene blue from aqueous solutions. It was reported that, doping of these transition metals has increased the catalyst maximum uptake 11.5 mg/g for pure titanium dioxide to 17.4 mg/g for V-doped titanium dioxide, 25.6 mg/g for Fe-doped titanium dioxide and 20.8 mg/g for W-doped titanium dioxide. These metal-doped titanium dioxide were further applied for removal of Pb(II), Zn(II), and Cd(II) from aqueous solutions, and it was found that, the highest removal percentage of Pb(II) was achieved by W-doped titanium dioxide, while Fe-doped titanium dioxide and V-doped titanium dioxide performed better for removal of Zn(II) and Cd(II) respectively. The kinetics of photocatalytic degradation of these heavy metals was carried out, where the maximum degradation percentages were found to be 4°C, at dosage of 1 g of catalyst, stirring speed of 600 rpm, and initial concentration of 25 ppm. |
