The Uptake of Hazardous Metal Ions into a High-Nuclearity Cluster-Based Compound with Structural Transformation and Proton Conduction
Wen Ma, Bing Hu, Jilong Li, Zhizhuan Zhang, Xi Zeng, Jiance Jin, Zhong Li, Shou‐Tian Zheng, Mei‐Ling Feng, Xiao‐Ying Huang
Abstract
The discovery of novel high-nuclearity oxo-clusters considerably promotes the development of cluster science. We report a high-nuclearity oxo-cluster-based compound with acid/alkali-resistance and radiation stabilities, namely, (H3O)7[Cd7Sb24O24(l-tta)9(l-Htta)3(H2O)6]·29H2O (FJSM-CA; l-H4tta = l-tartaric acid), which features a two-dimensionally anionic layer based on the largest Sb-oxo-clusters with 28-metal-ion-core [Cd4Sb24O24]. It is challenging to efficiently capture Sr2+, Ba2+ (analogue of 226Ra), and [UO2]2+ ions from aqueous solutions due to their high water solubility and environmental mobility, while it is unprecedented that a novel Sb-oxo-cluster-based framework material FJSM-CA can efficiently remove these hazardous ions accompanied with intriguing structural transformations. Especially, it shows fast ion-exchange abilities for Sr2+, Ba2+, and [UO2]2+ (reaches equilibrium within 2, 10, and 20 min, respectively) and high exchange capacity (121.91 mg/g), removal rate R (96%), and distribution coefficient KdU (2.46 × 104 mL/g) for uranium. Moreover, the underlying mechanism is clearly revealed, which is attributed to strong electrostatic interactions between exchanged cations and highly negative-charged frameworks and the strong affinity of (COO)− groups for these cations. Proton conduction of the pristine and Sr2+, Ba2+, [UO2]2+-loaded products was investigated. This work highlights the design of new oxo-cluster-based materials for radionuclide remediation and proton conduction performance.