Recent Advances in One-Dimensional Covalent Organic Frameworks for Gold Recovery from Electronic Waste

The efficient recovery of gold from electronic waste is of paramount significance, as such waste constitutes a valuable “urban mine” rich in precious metal resources, particularly gold. In the leaching liquor systems derived from e-waste, Au(Ⅲ) predominantly exists as AuCl₄⁻, amidst strongly acidic, high-salinity, and multi-metal coexisting conditions. Therefore, the critical challenge in the resource-oriented recovery of gold lies in achieving its selective recognition, efficient capture, and in-situ reduction from such complex matrices. Covalent organic frameworks (COFs) have attracted increasing attention in precious metal recovery, owing to their ordered pores, designable structures, and tunable functional sites. In particular, one-dimensional COFs (1D COFs) offer unique characteristics, including high exposure of active sites, low mass-transfer resistance, adjustable interchain interactions and directional electron transport, thereby providing a novel materials platform for the rapid enrichment and green reduction of AuCl₄⁻. This review summarizes recent progress in 1D COFs for gold recovery from electronic waste, focusing on strategies such as site-specific recognition, charge regulation, and photo- and photothermal-assisted reduction. The underlying mechanisms governing the adsorption and reduction behaviors of AuCl₄⁻ are elucidated, with emphasis on the roles of functional sites, interchain hydrogen bonding, protonation, photogenerated electrons, and photothermal effects. Finally, future perspectives are discussed, including the precise active-site construction, adaptability to complex leachates, cycling stability, continuous scaled-up recovery, and high-value utilization of recovered gold. This review is intended to engender interest in the development of low-cost, highly selective, and sustainable precious metal recovery using 1D COFs.