Proton‐Driven Multistage System Enables Selective Recovery of Gold and Palladium from Electronic Waste Leachate

Selective extraction of precious metals from urban mines plays a crucial role in mitigating the risk of depletion of precious metal resources and reducing waste pollution. However, a major obstacle in precious metal extraction lies in the difficulty of distinguishing the subtle differences in the physicochemical characteristics between them, especially gold and palladium. Herein, a proton‐driven separation system was presented for cascade recovery of gold and palladium from waste‐printed circuit boards (W‐PCBs) leachate using poly(amidoxime) (PAO) hydrogel. This exhibits an ultra‐high capacity, extra‐fast rate, and excellent selectivity for the extraction of Au(III) and Pd(II). Notably, the separation of Au(III) and Pd(II) can be achieved with high selectivity at pH = 0, resulting in a remarkable separation factor of k Au(III)/Pd(II) = 36.5. This was demonstrated to originate from the differential mechanism of PAO hydrogel for the capture of Au(III) and Pd(II) under proton‐mediated conditions. Drawing inspiration from the mechanism, the proton‐driven cascade recovery system demonstrates remarkable efficiency in sequentially recovering 99.92% of gold and 99.05% of palladium from W‐PCBs acid leachate. This research opens up a strategy to precisely separate and recover precious metals from e‐waste of urban mines.