Utilizing cost-effective pyrocarbon for highly efficient gold retrieval from e-waste leachate

• Published in: Nature communications Vol. 15; no. 1; pp. 6137 - 13
• Main Authors: Fu, Kaixing, Liu, Xia, Zhang, Xiaolin, Zhou, Shiqing, Zhu, Nanwen, Pei, Yong, Luo, Jinming
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 20.07.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 639/638/169; 639/638/169/896; Alginates; Alginic acid; Central processing units; Chlorine; Circular economy; CPUs; Economics; Electronic waste; Electrons; Gluons; Gold; Heavy metals; Humanities and Social Sciences; Hydroxylation; Ions; Leachates; Materials recovery; multidisciplinary; Noble metals; Nucleation; Phenolic compounds; Phenols; Reagents; Science; Science (multidisciplinary); Sorbents
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-50595-4

Addressing burdens of electronic waste (E-waste) leachate while achieving sustainable and selective recovery of noble metals, such as gold, is highly demanded due to its limited supply and escalating prices. Here we demonstrate an environmentally-benign and practical approach for gold recovery from E-waste leachate using alginate-derived pyrocarbon sorbent. The sorbent demonstrates potent gold recovery performance compared to most previously reported advanced sorbents, showcasing high recovery capacity of 2829.7 mg g −1 , high efficiency (>99.5%), remarkable selectivity ( K d  ~ 3.1 × 10 8 mL g −1 ), and robust anti-interference capabilities within environmentally relevant contexts. The aromatic structures of pyrocarbon serve as crucial electrons sources, enabling a hydroxylation process that simultaneously generates electrons and phenolic hydroxyls for the reduction of gold ions. Our investigations further uncover a “stepwise” nucleation mechanism, in which gold ions are reduced as intermediate gold-chlorine clusters, facilitating rapid reduction process by lowering energy barriers from 1.08 to −21.84 eV. Technoeconomic analysis demonstrates its economic viability with an input-output ratio as high as 1370%. Our protocol obviates the necessity for organic reagents whilst obtaining 23.96 karats gold product from real-world central processing units (CPUs) leachates. This work introduces a green sorption technique for gold recovery, emphasizing its role in promoting a circular economy and environmental sustainability. The demand for gold recovery from E-Waste is significant due to its high value. Here, authors present a practical method for extracting gold from an actual E-waste leachate using alginate-derived pyrocarbon. This approach yields a 23.96 karat gold product and demonstrates strong economic viability.