Abstract
The uptake behavior of anionic chelating agents into the magnesium-aluminium oxide precursor, Mg0.58Al0.28_??_0.14O (_??_: vacancy), prepared by the thermal decomposition of a synthetic Mg-Al carbonated layered double hydroxide, Mg0.67Al0.33 (OH) 2 (CO3) 0.16·0.46 H2O, was investigated at 25°C. The oxide solid solution was found to include highly the chelating agents such as ethylenediaminetetraacetate, its metal complexes, nitrilotriacetate and other similar anions as guest anion instead of CO2-3 ion from aqueous solutions with reconstructing the original hydrotalcite-like layer structure. The effect of initial solute concentration on the uptake was studied and isotherm parameters were evaluated. The Freundlich adsorption isotherm was found to be more suitable for all systems tested here and the values of the parameters, k and n, were quite higher. On the basis of the data, the relationship between the isotherm parameters and the number of negative charge, structure and arrangement of these anions in the interlayer of the resulting hydrotalcite-like compound was also discussed.
