The aim of this study is optimize and clarify the total mechanism of adsorption/ visible-photodegradation of Alizarin Red S polypropylene coated nano-TiO2 Degussa P-25 and TiO2 Anatase as photocatalysts. The characterization of Alizarin Red S and its chemical interaction with TiO2 surface has been studied. The acid dissociation constants of Alizarin Red S are determined. Adsorption and photodegradation steps were simultaneously studied in order to propose a simple kinetic model which can describe the process in an adequate way. The results obtained from this kinetics model are in good agreement with experimental data
