17 alpha ethinylestradiol EE2 photocatalytic degradation: adsorption isotherms and kinetics

Abstract

In the present study, the degradation kinetics and mineralization of EE2 by the TiO2 photocatalysis are examined in terms of UV absorbance of a wide range of initial EE2 concentration (mg.L-1) and photocatalyst loadings (0.5-24 µmol.L-1) in a reactor system. Different parameters are studied and described in details, such as adsorption under dark and UV-A conditions, photolysis, kinetics of degradation, ions impact on the isotherm adsorption of EE2, as well as the photocatalytic degradation. EE2 adsorption isotherm follows the Langmuir model. The photocatalytic oxidation kinetic of EE2 is described by the Langmuir–Hinshelwood model, and it follows a kinetic of order one for concentrations that are below 6 µmol.L−1, and then it reaches a plateau. For EE2, the coverage rates of the TiO2 surface in the dark and under UV exposure are different. Total Organic Carbon (TOC) analysis shows a complete mineralization of intermediate products.