Unlocking the Selective Extraction and Direct Reduction of Gold From E-Waste Leachate Through Robust Bismuth-Based...

The rapid increase in electronic waste (e-waste) and the growing demand for rare metals underline the urgent need for effective technologies to recover valuable elements such as gold from waste, a process known as urban mining. However, the development of sustainable and cost-effective adsorbents with high capacity and selectivity remains challenging. Here, two novel bioinspired bismuth metal-organic frameworks using the edible polyphenolic ellagic and gallic acids as building blocks, namely, bismuth-ellagate (Bi-EA) and bismuth-gallate (Bi-GA), are synthesized to evaluate for gold extraction from various matrices, including river water, seawater, and leaching solutions from computer central processing units (CPUs). Both chemically stable bismuth-based metal-organic frameworks (bioMOFs) exhibit an ultrahigh adsorption capacity (2989.9 mg/g for Bi-EA and 2516.3 mg/g for Bi-GA), with high Au³⁺ removal efficiency (> 99%) within 10 min, high selectivity, and recyclability. The excellent gold recovery performance is attributed to the adsorption-reduction mechanism resulting from the phenolic hydroxyl groups in these frameworks. This work provides a sustainable and cost-effective method for gold recovery with superior efficiency and environmental compatibility compared to existing technologies, thus contributing to the sustainable management of gold resources.