Gold(III) Recovery From HCl Solutions using Amberlite XAD-7 Impregnated with an Ionic Liquid (Cyphos IL-101)

Abstract

An ionic liquid (IL) (Cyphos IL-101) was immobilized on Amberlite XAD-7 using the dry impregnation method. Raw resin and extractant impregnated resins (EIR) were tested for Au(III) recovery from HCl solutions. Impregnating the resin increased sorption capacity. Au(III) was extracted by an ion exchange mechanism involving the binding of its chloro-complex to IL phosphonium cation. Sorption isotherms were very favorable with capacities up to 160 mg Au g⁻¹ EIR in 0.01 M HCl solution. Intraparticle diffusion controlled uptake kinetics. Au(III) was efficiently desorbed using thiourea (in HCl solutions). The EIR could be recycled maintaining high efficiencies for sorption and desorption for at least five cycles.

Keywords:

• Cyphos IL-101
• diffusion
• gold
• isotherms
• sorption extractant impregnated resin
• uptake kinetics

ACKNOWLEDGEMENTS

The authors thank the Franco-Mexican PCP program (Post-graduate Cooperation Program PCP No. 06/05), and the University of Guanajuato (CIAI 2008, 107/08) for financial support. Cytec Company is acknowledged for the gift of Cyphos IL-101 sample.

Notes

N is the molar ratio between the Cyphos IL 101 in the resin and gold at saturation of the EIR.

ERV: estimated error variance.