Kinetic Modeling Of The Photocatalytic Degradation Of Clofibric Acid

M. L. SATUF, A. MANASSERO, O. M. ALFANO

Florida

Conferencia; The 17th International Conference on Semiconductor Photocatalysis and Solar Energy Conversion (SPASEC-17); 2012

The occurrence of pharmaceuticals in the aquatic environment has become a subject of major concern due to their potential harmful effects. Particularly, blood lipid regulators are largely consumed and they are frequently detected in groundwater and drinking water. Clofibric acid (CA), the active metabolite of the lipid regulator clofibrate, is hardly biodegradable and cannot be completely eliminated in wastewater treatment plants. Photocatalytic degradation of CA has already been demonstrated. Furthermore, reaction intermediates have been identified and reaction pathways have been proposed. However, intrinsic kinetic data has not yet been published. The aim of the present work is to obtain a kinetic model to simulate the photocatalytic degradation of CA in slurry reactors. Experimental runs have been performed in a cylindrical reactor with a circular flat window.  Experiments have been carried out with different catalyst concentrations (0.1; 0.25; 0.5; 1.0 g/L TiO2 Degussa P25) and levels of irradiation (30, 65 and 100 %). Based on mechanistic reaction steps, kinetic equations for CA and two main intermediates, 4-chlorophenol (4-CP) and benzoquinone (BQ), have been developed.  The model accurately simulates the degradation of CA in a photocatalytic slurry reactor, and the obtained kinetic parameters are independent of the irradiation conditions and reactor geometry.