Novel immobilization of titanium dioxide (TiO2) on the fluidizing carrier and its application to the degradation of azo-dye

A photocatalyst was prepared by attaching TiO2 powder (diameter, 50 nm) in the sol state to fluidizing spherical ceramic carriers using a silicon binder. A high initial photocatalytic activity and strong attachment was obtained at a sintering temperature of 500 °C. An azo-dye (Orange-G) was used as the test contaminant to examine the photocatalytic effect of the new photocatalyst. The initial pseudo-first order degradation rate constant for Orange-G was 0.11 min−1. However, the photocatalytic activity doubled when boric acid was added to the silicon binder at a B to Si ratio of 106.5%. When sodium ethoxide was added to the silicon binder at a sodium ion to Si ratio of 15.0%, as much as 80% of the initial photocatalytic activity was maintained after the photocatalyst had been agitated at 180 rpm for 300 min. Adding both boric acid at a B/Si ratio of 106.5% and sodium ethoxide at a Na/Si ratio of 15% increased the photocatalytic activity and stability by three and four times, respectively.