Zhao Jie, Qiao Zelong, He Yuncheng, Zhang Rui, Li Han, Song Xuezhen, Cao Dapeng, Wang Shitao
State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, P. R. China.
Angew Chem Int Ed Engl. 2025 Jan 10;64(2):e202414366. doi: 10.1002/anie.202414366. Epub 2024 Oct 30.
The existing electronic waste (e-waste) and leaching solutions generated by industries accumulate significant amounts of gold (Au), even in excess of those in natural minerals. Therefore, the recycling of Au is extremely significant for the potential sustainability of chemical industry. By designing ionic covalent organic frameworks (COFs), here we synthesize a series of Ionic-COF-X (X=Cl, Br, AcO, and SO ) by anion regulation strategy and further explore their adsorption performance towards Au recovery. All these ionic COFs exhibit ultrahigh gold adsorption efficiency and excellent regeneration. Moreover, anion regulation could indeed affect the Au capture performance. In particular, when Cl ions serve as counter ions, the Au capacity of Ionic-COF-Cl could reach 1270.8 mg g. Moreover, in the actual CPU leaching solution test, the selectivity of Ionic-COF-Cl towards Au ion hits 39000 and 4600 times higher than that of Cu and Ni ions, respectively, suggesting that the Ionic-COF-Cl is a promising material for highly selective recovering gold from actual e-waste. DFT calculations further reveal that counter ions can regulate the adsorption affinity of ionic COF framework toward Au. In short, this work provides a useful anion regulation strategy to design ionic COFs as a promising platform for gold selective recovery from actual e-waste.
工业产生的现有电子废物（电子垃圾）和浸出溶液中积累了大量的金（Au），甚至超过了天然矿物中的含量。因此，金的回收对于化学工业的潜在可持续性极为重要。通过设计离子共价有机框架（COF），我们在此通过阴离子调控策略合成了一系列离子型COF-X（X = Cl、Br、AcO和SO），并进一步探索了它们对金回收的吸附性能。所有这些离子型COF均表现出超高的金吸附效率和出色的再生性能。此外，阴离子调控确实会影响金的捕获性能。特别是，当Cl离子作为抗衡离子时，离子型COF-Cl的金容量可达1270.8 mg g。此外，在实际的CPU浸出溶液测试中，离子型COF-Cl对金离子的选择性分别比Cu和Ni离子高39000倍和4600倍，这表明离子型COF-Cl是从实际电子废物中高选择性回收金的有前途的材料。DFT计算进一步表明，抗衡离子可以调节离子型COF框架对金的吸附亲和力。简而言之，这项工作提供了一种有用的阴离子调控策略，以设计离子型COF作为从实际电子废物中选择性回收金的有前途的平台。
