Synthesis and properties of 1-(2-aminoethyl)piperazine resin used in the sorption of the platinum group and gold ions

The optimum condition for synthesis of 1-(2-aminoethyl)piperazine resin (AEPZR) is molar ratio of reagents, piperazine/Cl = 3.0, reaction temperature 100°C, reaction time 10 h and 1,4-dioxane used as a solvent. The functional group capacity of AEPZR is 2.78 mmol FG/g resin. The structure of the resin was confirmed by FT-IR and elementary analysis. The sorption capacities of AEPZR for Au(III), Pd(II), Ru(III), Os(VI), Pt(IV), Ir(IV) are as high as 5.38, 3.67, 3.46, 3.10, 2.46, 2.24 mmol ion/g resin, respectively. The apparent activation energies of sorption of AEPZR for Au(III) and Pt(IV) are 24 ± 7, 28 ± 4 kJ/mol, individually. The sorption molar ratios (metal ion/FG molar ratio) were determined. The dynamic properties of sorption and elution were studied. Noble metal ions adsorbed on AEPZR can be eluted quantitatively by 2% thiourea in 0.1 mol HCl/l. The sorption mechanism was examined by X-ray photoelectron spectra.