Etude de l’adsorption et de la dégradation photocatalytique du colorant pharmaceutique Carmoisine Supra (CS) dans une suspension aqueuse de l’oxyde de titane (TiO2)

Abstract

In the water treatment field. Advanced oxidation processes (POA) are a promising alternative to conventional methods. It allows the degradation in aqueous medium of toxic organic and inorganic molecules recalcitrant to conventional methods. The aim of this study is to evaluate the effectiveness and the applicability of an advanced oxidation process, called heterogeneous photocatalysis (UV / TiO2) for the treatment of water polluted by dyes such as Carmoisine Supra (CS). In this process, often everything happens on the surface and the adsorption of organic compounds on the surface of the photocatalyst grains is the key step in the heterogeneous photocatalysis process. The amount of the adsorbed dye (CS) is measured by UV-Visible spectrum. The study has shown that it is advantageous to operate at room temperature, at basic pH with a quantity of TiO2 equal to 1g / L. The mechanism of adsorption on the chosen catalyst is described by pseudo-first order kinetics and that the adsorption isotherms of the dye on the catalyst are L-type (Langmuir). In addition, an application of several adsorption models (two, three and four parameters) has shown that the model of (Weber and Van Vliet) with four parameters is well suited to describe the experimental results while the models of (Fowler and Guggenheim) and (Hill and Boer) do not represent the experimental adsorption isotherm well. On the other hand, the photocatalytic degradation of this dye is carried out in aqueous suspension in the presence of titanium dioxide TiO2 in a Sun test CP+. The discoloration of the suspension is effective in determining the general mechanism of photocatalysis. The disappearance of the substrate follows pseudo first order kinetics and the Langmuir-Hinshelwood model is well suited to describe the kinetics of photocatalytic degradation of this dye