Aminal-Linked Porous Piperazine Covalent Organic Polymers for Gold Sequestration from E-Waste with Exceptional Performance Metrics

Adsorption is a highly efficient, scalable, and economically viable strategy for gold recovery from electronic waste, yet its practical implementation depends critically on the development of adsorbents with exceptional selectivity and capacity. Here, we report the molecular design, synthesis, and comprehensive characterization of two aminal-linked covalent organic polymers (COPs), DSK-1 and DSK-2, incorporating intrinsic metal-chelating functionalities. Among these materials, DSK-1 exhibits an extraordinary gold adsorption capacity of 5560 mg g–1, as evaluated by a pseudo-second-order kinetic model─representing the highest capacity reported for COP-based adsorbents to date. Moreover, DSK-1 displays remarkable selectivity toward Au(III) ions in complex electronic-waste leachates containing 12 competing metal ions, demonstrating its robustness under realistic extraction conditions. Collectively, these results underscore the potential of rationally engineered COPs as next-generation adsorbents for precious-metal recovery and highlight their promise as sustainable, high-performance materials for e-waste remediation.