Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.
Department of Chemistry, University of South Florida, 4202 East Fowler Avenue, Tampa, FL, 33620, USA.
Nat Commun. 2023 Mar 9;14(1):1284. doi: 10.1038/s41467-023-36591-0.
Developing an eco-friendly, efficient, and highly selective gold-recovery technology is urgently needed in order to maintain sustainable environments and improve the utilization of resources. Here we report an additive-induced gold recovery paradigm based on precisely controlling the reciprocal transformation and instantaneous assembly of the second-sphere coordinated adducts formed between β-cyclodextrin and tetrabromoaurate anions. The additives initiate a rapid assembly process by co-occupying the binding cavity of β-cyclodextrin along with the tetrabromoaurate anions, leading to the formation of supramolecular polymers that precipitate from aqueous solutions as cocrystals. The efficiency of gold recovery reaches 99.8% when dibutyl carbitol is deployed as the additive. This cocrystallization is highly selective for square-planar tetrabromoaurate anions. In a laboratory-scale gold-recovery protocol, over 94% of gold in electronic waste was recovered at gold concentrations as low as 9.3 ppm. This simple protocol constitutes a promising paradigm for the sustainable recovery of gold, featuring reduced energy consumption, low cost inputs, and the avoidance of environmental pollution.
为了维护可持续的环境和提高资源利用率，开发一种环保、高效且具有高选择性的金回收技术迫在眉睫。在这里，我们报告了一种基于精确控制β-环糊精与四溴合金酸阴离子形成的第二球配位加合物的相互转化和瞬时组装的添加剂诱导金回收范例。添加剂通过与四溴合金酸阴离子共同占据β-环糊精的结合腔，从而引发快速组装过程，形成超分子聚合物，作为共晶体从水溶液中沉淀出来。当使用二丁基卡必醇作为添加剂时，金的回收率达到 99.8%。这种共结晶对平面正方形的四溴合金酸阴离子具有高度选择性。在实验室规模的金回收方案中，在金浓度低至 9.3ppm 的情况下，从电子废物中回收了超过 94%的金。该简单方案构成了一种有前途的可持续金回收范例，其特点是能耗低、成本投入低且避免了环境污染。
