Kinetic studies of beta-blocker photodegradation on TiO2

The present work involves the photocatalytic degradation of common beta-blocker (acebutolol) on a recirculating spiral photo-reactor in presence of TiO2 under UV radiation (lambda = 365 nm). The effects of the initial concentration of acebutolol (5-30 mg/L), TiO2 dose (0.15-0.6 g/L), solution pH (4.8-10), UV lamp position (3-20 cm) and flow rate of the solution (140-525 mL/min) on the photodegradation are examined. It is found that the degradation rate of acebutolol decreases with decreasing the initial substrate concentration. The optimal pH of the acebutolol elimination is 7.1 and the photodegradation rate increases with raising the dose of TiO2. At high doses, the reaction is inhibited as a result of the light attenuation and shadowing effect. The increase of re-circulating speed leads to a decrease of the degradation rate. Under the operating conditions, the acebutolol photodegradation follows a pseudofirst- order kinetic and the Langmuir-Hinshelwood model is successfully used to fit the experimental data. (C) 2014 Published by Elsevier Ltd.