Purification of an iron contaminated vanadium solution through ion exchange resins

The present work aimed to study the behavior of four ion exchange resins: Lewatit (R) MonoPlus TP 209 XL, Lewatit (R) TP 207, DowexTM M4195 (chelating resins) and Lewatit (R) MonoPlus S 200H (strong cationic exchange resin) in the selective recovery of vanadium from an acid solution containing iron as an impurity. Batch experiments were carried out to evaluate the influence of parameters such as pH (0.50-2.00), resin mass (0.055-9.000 g) and temperature (293-328 K). Ion-adsorption mechanisms of the resins and thermodynamic parameters of adsorption reactions were evaluated. Increasing the pH from 0.50 to 2.00 favored the adsorption of both iron and vanadium by the resins. Chelating resins were more selective for vanadium than S 200H resin. Vanadium adsorption better adjusted to the Langmuir isotherm for the TP 209 XL, TP 207 and S 200H resins, while M4195 adjusted better to the Temkin isotherm. The iron adsorption mechanism, however, varied between the Langmuir, Freundlich and Temkin models. The positive values of Delta H0 expressed the endothermic nature of the vanadium adsorption process for the three chelating resins and for iron in all of them. Furthermore, negative Delta G0 values revealed a spontaneous character of the adsorption of both metals to all of the resins. In terms of mass of adsorbed ions, chelating resins showed good selectivity for vanadium compared to iron and these are, therefore, promising to obtain pure vanadium solutions in greater scale operations.

Automated summary

This study investigated the behavior of four ion exchange resins in the selective recovery of vanadium from an acid solution containing iron as an impurity. The chelating resins showed higher selectivity for vanadium, with better fitting to Langmuir isotherm, indicating potential for obtaining pure vanadium solutions in larger scale operations. Positive values of Delta H0 indicated endothermic nature of vanadium adsorption, while negative Delta G0 values revealed a spontaneous character of adsorption process for both metals to all resins.