Title: La-doped ZnTiO3 or TiO2 and supported on ecuadorian diatomaceous earth as a highly efficient photocatalyst driven by solar light

Abstract

Nowadays, there is a great interest in the use of TiO2 for photocatalytic remediation of wastewater. Doping, heterojunction and immobilization on porous materials are effective methods to improve the photocatalytic efficiency of this semiconductor. In this study, ZnTiO3/TiO2 (ZTO) and ZnTiO3/TiO2/La (ZTO/La) nanocomposites were successfully prepared by the sol-gel method and immobilizing on diatomaceous earth (DE). The composition and texture of the prepared composites were characterized by X-Ray diffractometry (XRD), X-Ray Fluorescence (XRF), Diffuse Reflectance Spectroscopy (DRS), Scanning Electron Microscopy (SEM-EDX) and specific surface area (SSA). The adsorption capacity and photocatalytic activity of composites were determined via degradation of methylene blue (MB) in batch reactors. The materials evaluated were prepared in the shape of 0.2 cm (diameter) and 1.0 cm (length) cylindrical extrudates. The results indicated that the ZTO/La-DE composite exhibits a higher efficiency of removal of MB than ZTO-DE and DE under solar irradiation. The Langmuir isotherm model and the pseudo-second-order model were better suited to the adsorption process. The higher degradation percentage of MB obtained was 96% after 150 min of irradiation. The results reflect that synthesized composite could be used potentially for the removal of cationic dye from wastewater.