Efficient and selective gold recovery from e-waste by imidazolium-based poly(ionic liquid)s

Recycling gold from e-waste is not only beneficial to environmental protection, but also to resource sustainability. However, it remains a great challenge due to the limitations of high cost, lengthy balance process and the interference of coexisting metals. Herein, a family of low-cost, nitrogen-rich content and acid-stable imidazolium-based poly(ionic liquid)s, designated as P(nDVB-mVBIMCl)s, were synthesized for recovery of gold from e-waste. The obtained P(2DVB-8VBIMCl)s achieves outstanding adsorption capacity (820.5 mg·g−1) and rapid equilibrium time (15 min) and satisfactory reusability (more than 8 cycles). XPS, EDS and ion chromatography revealed that the excellent adsorption performance was attributed to synergistic effect of ion exchange and chemical reduction. In addition, the P(2DVB-8VBIMCl)s showed excellent selectivity for gold in actual e-waste leaching solution, exhibited satisfactory selectivity coefficient for Fe3+ (1.46 × 104) and Ni2+ (1.12 × 104), obtaining 23.4 karat high-purity gold after calcination. In addition, the P(2DVB-8VBIMCl)s shows its good economic feasibility. Overall, this work provides a feasible adsorbent, which becomes a promising candidate for industrial gold recovery from e-waste.