Equilibrium and kinetic studies on chromium(VI) removal by a mixed oxide derived from MgAl layered double hydroxide

A magnesium aluminium hydrotalcite-like compound (HT) containing carbonate anions in the interlayer space and with a final Mg/Al ratio of 2 was synthesized by the coprecipitation method. The obtained material was characterized by powder X-ray diffraction (XRD), Fourier-Transform-Infrared spectroscopy (FT-IR), thermal analysis (ATG/ATD), and surface area measurements (BET). The interaction of the clay with Cr(VI) has been studied by ultraviolet-visible (UV-vis) spectroscopy. The calcined hydrotalcite (HT-C) showed the highest capacity of removal of chromium ions, and their sorption capacities for Cr(VI) are 4.85 mmol/g. The effect of various parameters on the preparation conditions for the removal of chromium, such as the contact time, the amount of sorbent, the initial concentration of Cr(VI), and the pH values of aqueous solution were also investigated to identify their influence on Cr(VI) sorption. The characterization of the calcined hydrotalcite (HT-C) after interaction with Cr(VI) ions by FT-IR spectroscopy showed that Cr(VI) was adsorbed and intercalated by the solid. (C) 2014 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.