Immobilization of mesoporous-assembled TiO₂ nanocrystal photocatalyst for degradation of Azo dye contaminant in wastewater

Abstract

Photo catalysis is an advanced oxidation process that efficiently degrades organic contaminants present in wastewater effluents. The suspension of TiO2 powders in wastewater during the photocatalytic treatment shows great photo activity, but it requires further troublesome filtering process to separate the photo catalyst from the treated wastewater. Therefore, utilization of TiO2 in an immobilized mode is more practical because it solves the problems of TiO2 separation and reuse as compared to a suspension mode. This work focused on the photocatalytic degradation of Acid Black (AB) diazo dye by using nanocrystal line mesoporous-assembled TiO2 photo catalyst immobilized on a glass plate, where the mesoporous-assembled TiO2 nanocrystal was synthesized by a sol-gel process with the aid of a structure-directing surfactant. Various preparation parameters during the immobilization step were investigated on the photocatalytic AB dye degradation performance. The experimental results showed that the mesoporous-assembled TiO2 film with 5 wt.% P-25 TiO2 addition and calcined at 400 ℃ provided the highest AB dye degradation rate constant of 0.23 h-1. Moreover, an increase in the number of coated TiO2 layers was found to enhance the photocatalytic activity until reaching the peel-off limitation at 4 layers.