| The high gravity environment generated in a rotating packed bed (RPB) through the action of centrifugal force causes aqueous raw materials to shred into smaller nano-droplets and thin films, thus considerably intensifying mass transfer and mixing processes. Consequently, high mass transfer, uniform supersaturation and homogenous nucleation are achieved in a shorter residence time. This minimizes chances of agglomeration; thus yielding nanoparticles with narrower size distribution and hence better properties.This study aimed to synthesize coupled ZnO/TiO2nano-photocatalyst in a rotating packed bed, and its subsequent application in treatment of textile wastewater. The as-prepared nanoparticles were characterized by X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FE-SEM). Their photocatalytic activity, evaluated by degrading a model textile dye-Rhodamine B (RhB) under UV irradiation, was observed to be influenced by the molar ratio of zinc salt to titanium salt, concentration of zinc and titanium salts, rotational speed of RPB, flow rates of the liquids into RPB and the initial pH of the dye solution. Comparison of their characteristics and photocatalytic activity with those prepared in a stirred tank reactor (STR) under similar conditions revealed that RPB produces nanoparticles of better characteristics and higher photocatalytic activity; reaching a maximum of99.3%after3hours of irradiation as compared to81.6%by those of STR. This research therefore provides a simple approach for large scale production of coupled ZnO/TiO2nano-photocatalyst with enhanced photocatalytic activity. |
