Chromium (III) removal by microporous ion exchanger Amberlite.120 (Na+): kinetic, equilibrium and thermodynamic studies

Cr (III) sorption on microporous strong cation exchanger Amberlite.120 (Na⁺) is studied as a function of time and temperature. The pH changes show the co-sorption of H⁺ ions along with the chromium. The rate constant values for Cr (III) sorption are calculated for both film and particle diffusion processes. However, the particle diffusion is found to be more dominant than the film diffusion. The temperature is found to have a positive effect on both the diffusional processes. The low values of energy of activation also confirm the diffusional nature of the process. Equilibrium data are explained with the help of Langmuir equation. Various thermodynamic parameters (??H, ??S and ??G) for Cr (III) exchange on the resin are calculated. The ??G values are found to be negative, while both the ??H and ??S values obtained are positive.