Photocatalytic Removal of Food Colorant E 131 VF from synthetic wastewater by Cu Doped TiO2 Samples

In this work, we studied the effect of various amounts (0.2-1.2 % mole ratio) of Cu doping to TiO2 nanoparticles (Cu/TiO2) on the photocatalytic removal efficiency of the food colorant E 131 VF. Two series of doped TiO2 (P25) photocatalysts were prepared in two different media (50%ethanol-50%acetone and 5% surfactant (Tween 20)-95%H2O) by using the impregnation method. The prepared samples were characterized by XRD, FTIR, Raman, diffuse reflectance spectroscopy and SEM/EDX analyses. The XRD results showed that the crystal dimension of TiO2 increased from 23 to 35 nm and rutile/anatase ratio decreased from 16% to 9% after Cu doping in two different media. The photoactivity of TiO2 was reduced in the presence of Cu even at a low molar ratio. The photocatalytic degradation rate constant of TiO2 (P25) was 0.24 (au) but it decreased to 0.015 (au) in the presence of the sample containing 0.6% Cu. Several reasons were suggested to explain the dramatic decrease in the activity of the prepared Cu/TiO2 samples.