Use of Multivariable Analysis (ANOVA) to Compare Irradiation Sources on Diuron Destruction by Photocatalysis Using TiO2-P25 Impregnated with Sm3+, Eu3+ and Gd3+

Abstract

Ions of Sm 3+ , Eu 3+ and Gd 3+ were deposited onto the surface of TiO 2-P25 using an impregnation method, and the catalysts were calcined to 500°C in order to provide thermal stability to the crystalline phases. A sample of pure P25 was processed under the same synthesis conditions. The materials were characterized by physisorption of N 2 , X-ray diffraction and Scanning Electron Microscope and Spectroscopy UV-Vis with diffuse reflectance. It was observed by SEM that P25 had an amorphous surface forming irregular aggregates and deformations in which the studied lanthanide ions were inserted. Due to heat treatment, the P25 suffered modifications that showed a higher photocatalytic activity in the visible region, by the presence of oxygen vacancies generated by the removal of impurities (C and Cl). XRD analyses determined the distribution and crystal size of the crystalline phases presented in the P25 (anatase and rutile). Lanthanide ions possibly demonstrated an effect of superficial coalescing in the rutile phase of the P25. A completely randomized experimental design was used to determine the catalytic evaluation, and sunlight was statistically shown to be the best condition for the degradation and mineralization of diuron. Comparing treatments indicated a better option: using the catalyst with 0.3 wt% Gd under sunlight.