Study of the adsorption process of textile dye AG1 by a mixed oxide derivative of anionic clay

Abstract

Layered double hydroxides (LDH) are anionic clays with high anion exchange capacities. Calcination of LDH increases significantly their retention capacities. In the present study, calcined products (CLDH) were obtained by heating [Zn 2 -Al-CO 3 ] at 500°C. The adsorption of the textile dye Acid Green 1 (AG1) by CLDH was performed at different pH values, the textile dye-adsorbent contact time and mass ratio AG1/CLDH. The equilibrium at room temperature is reached after 24 h, this is confirmed by rapid kinetic modeling of the experimental data by the pseudo-second order model. The adsorption is described by Langmuir-type isotherm. The study of adsorption isotherms, comparison with the retention of a carbonated phase of calcined and uncalcined, reveals that the first could be a good candidate for trapping such pollutants. Characterization of the CLDH solids, both fresh and after removal of AG1 by X-ray diffraction and infrared spectroscopy shows that the adsorption is also enhanced by reconstruction of a matrix hydrotalcite intercalated by AG1 at high concentration. The removal of textile dye in anionic form by CLDH gave satisfactory results. Under optimum conditions, the retention is total (100%) when the weight ratio AG1/CLDH is between 0.38 and 0.68. Retention capacity reached 800 mg/g.