Removal of organic matter from waters by rare earth ions doped TiO2

In this thesis, a photocatalyst was produced by coating lanthanum (La) and TiO2 on micro-sized glass beads whose surfaces were made porous by using hydrofluoric acid and its humic acid removal efficiency from water was investigated. Glass beads were added to facilitate the separation of TiO2 from the solution after treatment and to increase the adsorption ability of the photocatalyst, while La was added to provide photocatalysis efficiency under visible radiation. The structural properties of the produced photocatalyst were investigated by scanning electron microscope-energy dispersion X-ray (SEM-EDX), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyzes. The efficiency of the photocatalyst in the removal of humic acid from aquatic environments under visible light was investigated. For this purpose, Taguchi experimental design was applied and the amount of photocatalyst, initial solution pH, reaction time, initial humic acid concentration and light intensity were selected as independent variables. A set of 5 factors and 3 levels of orthogonal arrays were created and batch experiments were performed for humic acid removal. The results were evaluated by analysis of variance (ANOVA). The highest humic acid removal was determined as 54.07% under the conditions of 0.4 g/L photocatalyst amount, initial pH value of 10, 30 min reaction time, 20 mg/L humic acid concentration and 18 W light intensity. The effect rank of the independent variables on humic acid removal was determined as the amount of photocatalyst, initial solution pH, light intensity, reaction time and humic acid concentration, according to the signal/noise (S/N) ratios. According to the ANOVA results, when the P values were examined, it was determined that the amount of photocatalyst was statistically at 95% significance level, and other parameters were not significant.