Removal of Direct Blue 71 Dye from Aqueous Media in a Photocatalytic Fixed Bed Reactor, Containing LECA Granols Coated by TiO2-Ce Nanoparticles

The separation of nanocatalysts from the liquid phase often limits their use in industrial-scale processes due to their small size. To solve this problem, nanocatalyst is often embedded on the substrates. In this study, at the first stage, cerium doped TiO2 nanoparticles were prepared by the sol-gel method. Then, LECA granules are used as a support phase for immobilizing nanoparticles. Nanoparticles are characterized by Fourier-transform InfraRed (FT-IR) spectroscopy, X-Ray Diffraction (XRD), Field-Emission Scanning Electron Microscopy (FE-SEM), and nitrogen adsorption-desorption isotherms (BET). The FE-SEM studies showed a uniform coating of TiO2-Ce nanoparticles on the surface of LECA granules. A catalytic bed was constructed with a regular arrangement of the LECA granules and immersed in a photoreactor with the cyclic flow. The degradation of direct blue 71 (DB71) was investigated in the fixed bed photoreactor. The results showed that the fixed bed configuration (5.3gr) could remove about 96% of the dye (DB71, 20ppm) during 1h irradiation under a UV light source. Furthermore, the ability of coated LECA granules in the degradation of dye was studied in the floating condition under sunlight. The results showed that with daily irradiation for 4 h, the catalyst can remove 94% of the color over three days.