Junli Wang, Chen Luo, Wentao Wang, Hui Wang, Jiaxuan Shi, Taihong Yan, Jianwei Li
State Key Laboratory of Chemical Resources Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
Department of Radiochemistry, China Institute of Atomic Energy Beijing, 102413, China.
Langmuir. 2024 Oct 22;40(42):22006-22014. doi: 10.1021/acs.langmuir.4c02071. Epub 2024 Oct 10.
Efficiently adsorbing Pd(II) from acidic radioactive waste liquid is crucial for ensuring the safety of the radioactive waste vitrification process and significantly alleviating the scarcity of precious metals. However, the stability and selectivity of most current adsorbents are limited, hindering their practical application under acidic conditions. To address these limitations, a covalent organic framework (DHTP-TPB COF) was prepared with a high nitrogen content, leveraging the high affinity of its soft ligand with palladium to achieve high selectivity. This work demonstrated that DHTP-TPB COF exhibits rapid adsorption kinetics, with equilibrium achieved within 10 min. The framework also boasts a high adsorption capacity of 142.8 mg/g and impressive reusability in 1.0 M nitric acid. Moreover, the DHTP-TPB COF displays excellent selectivity for Pd(II), even in the presence of 13 interfering ions. By combining FT-IR, XPS spectroscopy, and DFT theoretical calculations, the dense sites in the framework have a strong affinity for Pd(II), resulting in exceptional adsorption performance that was confirmed. The findings of this study highlight the potential of COFs with robust linkers and customized functional groups to effectively and selectively capture Pd(II) under harsh environmental conditions of high-level liquid waste.
从酸性放射性废液中高效吸附钯（II）对于确保放射性废物玻璃固化过程的安全性以及显著缓解贵金属的稀缺性至关重要。然而，目前大多数吸附剂的稳定性和选择性有限，阻碍了它们在酸性条件下的实际应用。为了解决这些限制，制备了一种具有高氮含量的共价有机框架（DHTP-TPB COF），利用其软配体与钯的高亲和力实现高选择性。这项工作表明，DHTP-TPB COF表现出快速的吸附动力学，在10分钟内达到平衡。该框架还具有142.8 mg/g的高吸附容量以及在1.0 M硝酸中令人印象深刻的可重复使用性。此外，即使存在13种干扰离子，DHTP-TPB COF对钯（II）仍表现出优异的选择性。通过结合傅里叶变换红外光谱（FT-IR）、X射线光电子能谱（XPS）和密度泛函理论（DFT）计算，证实了框架中的密集位点对钯（II）具有很强的亲和力，从而产生了卓越的吸附性能。这项研究的结果突出了具有坚固连接体和定制官能团的共价有机框架在高放废液的恶劣环境条件下有效且选择性地捕获钯（II）的潜力。
