A comparison of slurry and immobilized TIO2 in the photocatalytic degradation

Abstract

The photocatalytic degradation of phenol was studied using slurry and immobilized TiO2 as catalysts in order to compare the specific reaction rate constants, ks and kp. Losses from phenol evaporation, the time necessary to reach adsorption equilibrium, irradiation effects and photolysis rates were quantified. ks was determined under rateoptimizing operating conditions, and kp was determined using the amount of immobilized catalyst mass that gave the maximum pollutant degradation rates. ks was two times larger than kp when the calculations were made on catalyst mass basis. Experiments performed to study catalyst deactivation showed that kp was approximately one-half of its initial value after 18 hours of phenol photodegradation. Also, among the photocatalytic degradation reactions of rhodamine B, tetracycline and phenol, the ratio of ks to kp was between 2.1 and 5.3 when the calculations were made on catalyst mass basis.