TITANIUM DIOXIDE SOL-GEL/ZINC OXIDE POWDER-COATED CLAY BEADS IN PHOTOCATALYTIC REACTOR

Catalyst Immobilization methods are important for providing better recovery of catalyst in photocatalytic treatment. The aim is to characterize and evaluate the photocatalytic performance of TiO2/ZnO-coated clay beads. The titanium dioxide/zinc oxide (TiO2/ZnO)-coated clay beads were prepared via the sol-gel process. Various ZnO powder ratios gave different TiO2/ZnO composites sol. Four layers of TiO2/ZnO sol were coated on clay beads and dried in the oven at 100 & DEG;C for 30 min. The coated clay beads were calcined at 500 & DEG;C for one hour for every two layers. Characterization of coated clay beads was done using a scanning electron microscope and energy dispersive spectroscopy. The increased surface area on small agglomeration and optimum loading of ZnO (5 g) resulted in the highest degradation efficiency recorded at 86.57%. An effective catalyst immobilization achieved a good recycling performance on clay beads. Degradation rate data were presented by pseudo-first-order kinetics. It was observed that the average degradation rate for TiO2/5 g ZnO is 0.00836 min-1. The actual results in this work can be applied as a guideline for the preparation of TiO2/ZnO-coated clay beads with high photocatalytic performance.