Adsorption of zinc onto anionic ion-exchange resin from cyanide barren solution

Removal of zinc from cyanide barren solution is obligatory for its reuse in leach process. Batch experiments were carried out to evaluate the adsorption capacity of resins under different experimental conditions, including concentration, resin amount, initial pH, contact time and temperature. More than 99% of adsorption was achieved under the optimal condition. High adsorption rates on the resin were observed at the beginning and plateau values were obtained in 60 min. The thermodynamic parameters (free energy change ΔG, enthalpy change ΔS and entropy change ΔH) for the adsorption were evaluated. The adsorption kinetic mechanism was studied with four models. The experimental results show that the adsorption follows the Langmuir isotherm and the kinetics follows the pseudo-second-order model.

Graphical abstractIn order to recycle the cyanide barren solution, strong alkali anion exchange resin D201 × 7 was used to adsorb zinc. More than 99% adsorption was achieved under optimal conditions. High adsorption rates on the resin were observed at the beginning and plateau values were obtained in 60 min. EDS image indicated that chorine ion in the original exchange resin was substituted by Zn(CN)42 −. Thus it is an appropriate sorbent for the treatment of cyanide barren solution.Figure optionsDownload full-size imageDownload as PowerPoint slide