Open-Framework Vanadate as Efficient Ion Exchanger for Uranyl Removal

作者：Cheng Meng, Mingyang Du, Zhibin Zhang, Qian Liu, Chunpei Yan, Zifan Li, Zhimin Dong, Jianqiang Luo, Jianguo Ma, Yunhai Liu, Xiangke Wang · 发表于：Environmental Science & Technology · 年份：2024 · DOI：10.1021/acs.est.4c03703 · 被引用次数：70 · 研究领域：Radioactive element chemistry and processing、Chemical Synthesis and Characterization、Metal Extraction and Bioleaching

The elimination of uranium from radioactive wastewater is crucial for the safe management and operation of environmental remediation. Here, we present a layered vanadate with high acid/base stability, [Me 2 NH 2 ]V 3 O 7, as an excellent ion exchanger capturing uranyl from highly complex aqueous solutions. The material possesses an indirect band gap, ferromagnetic characteristic and a flower-like morphology comprising parallel nanosheets. The layered structure of [Me 2 NH 2 ]V 3 O 7 is predominantly upheld by the H-bond interaction between anionic framework [V 3 O 7 ] n n – and intercalated [Me 2 NH 2 ] + . The [Me 2 NH 2 ] + within [Me 2 NH 2 ]V 3 O 7 can be readily exchanged with UO 2 2+ . [Me 2 NH 2 ]V 3 O 7 exhibits high exchange capacity ( q m = 176.19 mg/g), fast kinetics (within 15 min), high removal efficiencies (>99%), and good selectivity against an excess of interfering ions. It also displays activity for UO 2 2+ ion exchange over a wide pH range (2.00–7.12). More importantly, [Me 2 NH 2 ]V 3 O 7 has the capability to effectively remove low-concentration uranium, yielding a residual U concentration of 13 ppb, which falls below the EPA-defined acceptable limit of 30 ppb in typical drinking water. [Me 2 NH 2 ]V 3 O 7 can also efficiently separate UO 2 2+ from Cs + or Sr 2+ achieving the highest separation factors (SF U/Cs of 589 and SF U/Sr of 227) to date. The BOMD and DFT calculations reveal that the driving force of ion exchange is dominated by the interaction bet...