Efficient and selective adsorption of Au(iii), Pt(iv), and Pd(ii) by a radiation-crosslinked poly(ionic liquid) gel

Abstract

It is necessary to recover precious metals from aqueous solutions because they have a wide range of applications. In this work, a poly(ionic liquid) (PIL) gel containing an imidazole group was fabricated using a radiation method and utilized for the capture of Au(III), Pt(IV), and Pd(II) ions. It was discovered that the PIL gel exhibited high adsorption efficiency for Au(III), Pt(IV), and Pd(II) in a wide pH range. The adsorption processes for target ions all reached equilibrium within 4 min. Meanwhile, the isotherm experiments revealed that the adsorption was in accordance with the Langmuir model, and the maximum adsorption capacities were 854.7 mg g⁻¹ for Au(III), 420.2 mg g⁻¹ for Pt(IV), and 277.8 mg g⁻¹ for Pd(II). Furthermore, the PIL gel could selectively adsorb Au(III), Pt(IV), and Pd(II) from simulated acidic waste effluent containing Cu(II), Zn(II), Fe(III), and Ni(II). In particular, the PIL gel demonstrated its ability to selectively recover trace Au(III) from real gold slag leaching solution. FTIR and XPS analyses revealed that anion exchange was the dominant adsorption mechanism.