SUMMARY
The purpose of this work is to observe and to interpret the types of interactions between aluminium sulphate and aromatic organic compounds such as catechol (hydroxyl function) and phenylalanine (amino-acid). The influence of different reaction parameters such as the coagulant dose, the pH effect and the initial concentration of the organic compound are tested by means of Jar test trials. All this is done in distilled water. The results obtained can suggest that the chemical structure of the compound and the nature of the functional groups (hydroxyl or amine) could condition the effectiveness of the flocculation of these substances. The main mechanisms would be either a physical adsorption, a ligand exchange or a complexation on the surface of the aluminum hydroxide flocs.