Elimination de polluants organiques par des argiles de synthèse. Cas des colorants de l’industrie textile

Abstract

We have examined the way that the methylene blue is held by Na-montmorillonite and alumina intercalated clay. We used several physico-chemical methods of analysis (X-ray powder diffraction, infrared absorption spectrometry…) to clarify the effect of the introduction of the Al13 polycations between the clay layers on its physico-chemical and structural properties. Our results show that the mechanism of fixing of the dye on intercalated clay is more complex than a simple cationic exchange and involves the surface groups of the pillars. Solutions containing from 0 to 1 mmole/l of this dye were successfully treated. The removal capacities of these materials are approximately 1.87 and 1.65 mmole/ methylene blue per g, for the Na-montmorillonite and alumina intercalated clay, respectively. The removal of the color of aqueous solutions of chlorophénol Red (acid dye) by adsorption on synthetic anionic clay (hydrotalcite [Mg-Al-CO3]) was investigated. The solid, synthesized by coprécipitation at constant pH, was characterized by X-ray powder diffraction. The interaction of the clay with this dye shows that the kinetic of adsorption follows the second order model. The influences of the pH, the mass of the adsorbent, the initial concentration of dye were studied in order to optimize adsorption. The treatment of solutions containing 0 to 1.5 mmole/l of dye was successful. The adsorption capacitie of this calcined material for the chlorophénol Red is close to 1.94 mmole/g. The study of the adsorption reversibility indicates that it is possible to use this anionic clay like adsorbents recyclables for the water treatment polluted by this dye.