etud experimentale de l'oxydation photocatalytique les anti inflammatoires non steroidiens de diclofenac sodique dans une suspension

Abstract

Advanced oxidation (POA) processes are a promising alternative to conventional methods in the field of water treatment. They allow degradation in aqueous medium toxic organic and inorganic molecules recalcitrant to conventional methods. The aim of this study is to evaluate the efficiency and the applicability of an advanced oxidation process, called heterogeneous photocatalysis (UV / TiO2), for the treatment of waters polluted by anti-inflammatories such as Diclofenac. In this work, the photodegradation of Diclofenac is carried out at room temperature in an aqueous suspension of TiO 2 in an experimental device equipped with a UV lamp. In the case of photocatalysis, the essential phenomena occur on the surface of the TiO2 photocatalyst, that is why part of this work is dedicated to the study of the adsorption of Diclofenac on the surface of TiO2 particles. The amount of the adsorbed Diclofenac is measured by UV spectroscopy. The study has also shown that it is advantageous to operate at room temperature, at basic pH and a TiO2 concentration of 1 g / L. Blanchard's pseudo-second order kinetic model best represents our experimental kinetics compared to Lagergren's pseudo-first order model. Several models of two and three parameter adsorption isotherms were tested to model the experimental adsorption equilibria. The value of RL obtained from the Langmuir model indicates favorable adsorption. The value of 1 / n obtained from the Freundlich model indicates better adsorption. The adsorption energy was evaluated by the Temkin model. All three-parameter models tested apply well to the experimental results. The order of applicability of the models is as follows: Langmuir-Freundlich> Redlich Peterson> Langmuir> Temkin> Sips> Freundlich. Better degradation is obtained in ZnO2 Fe2O3. The degradation efficiency of Diclofenac strongly depends on the operating conditions. The rate of disappearance of Diclofenac increases with the increase of the TiO2 mass, the optimal amount of TiO2 equal to 1 g / L. The best degradation yield has been found for basic pHs. Ambient temperature promotes degradation. The initial rate of degradation is proportional to the initial concentration of Diclofenac. The degradation is almost zero by photolysis. In the presence of TiO2, the degradation of Diclofenac becomes more important. Faster degradation is achieved with the fenton process. Complete degradation of Diclofenac was obtained after 15 min. The Langmuir-Hinshelwood L-H model clearly describes the photocatalytic degradation kinetics of Diclofenac, therefore photocatalytic reactions occur on the surface of TiO2 particles