Abstract
This paper dealt with Cr(VI) sorption on isomorphic substituted Mg/Zn-Al - type hydrotalcites under proper working conditions. The prepared samples were named Mg3Al, Mg2ZnAl, Mg1.5Zn1.5Al, MgZn2Al and Zn3Al. The experimental data concerning sorption isotherms were modelled in accordance with four equilibrium equations: Langmuir (L), Freundlich (F), Langmuir-Freundlich (L-F) and Redlich-Peterson (R-P) by using two ways: (i) estimation of qmax, K and n; and (ii) estimation of K and n, for qmax values equal to the experimental maximum uptake value. It was proved that Langmuir-Freundlich model was the best solution for fitting the experimental data. The results also allowed setting up a ranking order of the sorption capacities for the studied hydrotalcites.