Advanced oxidation processes have been investigated as a viable means of treatment for the degradation and removal of dye-containing effluents. In this work, the degradation of an azo dye, Eriochrome black, was studied using a novel photocatalytic reactor in which TiO 2 is immobilized on a rotating corrugated drum. The degradation of the dye via the photocatalytic method was confirmed, and degradation rates were compared using different drum designs. Catalyst deactivation was observed, and this process of irreversibility was found to increase with increasing initial dye concentration in the water. A Langmuir-Hinshelwood kinetic analysis was applied, and it was found to agree well with the data in the initial parts of the reaction but diverged with increasing time. The discrepancy was thought to be due to the presence of unquantified reaction intermediates which may only be broken down slowly by the photocatalytic process.