Effects of Flow Pattern on Photodegradation of Phenol and MB with TiO2 Thin Film Immobilized on Ceramic Tube

This study focuses on the effects of two flow patterns on photo degradation of organic compounds with TiO₂ film immobilized on the inner wall of glazed ceramic tube. Pattern 1 is to pump the solution into the tube from the bottom and overflow from the top. Pattern 2 is to spray the solution on the inner surface and flow from the top to the bottom along the inner wall. Experimental results indicated that the first-order reaction rate constants for photo degradation of phenol with pattern 1 is about 2 times of that with pattern 2 because phenol can be directly degraded easily by UV lights. However, the corresponding degradation rate constants of MB with pattern 2 is about 2 to 3 times of that with pattern 1 because MB can not be directly degraded easily by UV lights. In addition, effects of tube radius and extinction coefficient on the reaction constant were also studied. The rate constant will increase with the decrease of extinction coefficient while the tube radius is fixed, and an optimal tube radius for the maximum value of reaction rate constant can be found while extinction coefficient is fixed.