The recovery of Au(III) by hydrogel-like beads

The significance of recycling gold is self-evident. However, existing technologies for recovery of gold show several disadvantages, including their high costs, difficulty to recover adsorbent, as well as low adsorption capacity. Thus, an ecofriendly gold recovery system with low cost and high efficiency should be developed. In this study, a novel RFT-SA adsorbent (RFT:SA = 1:1) was developed, which was achieved by wrapping the self-assembled resorcinol-formaldehyde-thiourea (RFT) in sodium alginate (SA) hydrogels. This study suggests that it can make up for the shortcomings of powder adsorbent RFT that is difficult to collect, and it can fully use the high adsorption capacity and high selectivity of RFT. The RFT-SA adsorbent exhibited high adsorption capacity as Au(III) reached 603.4 ± 24.6 mg g−1 of MAu/Mdry-gel. It is noteworthy that RFT-SA exhibited excellent selectivity to Au(III) in simulated electronic waste leachate containing Au(III) and other competing ions, thus suggesting that RFT-SA can recover gold efficiently under complex conditions. This study can provide a new idea for designing a novel type of adsorbents for precious metal ions with high adsorption capacity, high selectivity and being easy to collect for the efficient recovery of precious metals from electronic waste leachate.