Photocatalytic Decomposition of Organic Dyes Using a Rotating Cylinder System

In this study, a rotating cylinder system was used in the photocatalytic decomposition of organic dyes in aqueous medium for water purification. To this end, the titania nanoparticle dispersion was mixed with an organic dye solution under a rotating inner cylinder at controlled speed. The rate constant was adjusted by changing the speed of rotation to determine the optimal circulating velocity. Since nanoparticle dispersion is a secondary contaminant after wastewater treatment, the titania paste was deposited on the inner surface of the stationary outer cylinder to form a photocatalytic film. During repeated batch-mode operation, the deactivation of the deposited film was analyzed by measuring the rate constant as a function of time. Continuous operation was also used to remove organic dye in the water to study factors affecting the removal efficiency of methylene blue. Higher rotating velocity and slow feed rate facilitated the removal of contaminants via desorption of adsorbed dyes with adequate retention time.