Halogen microregulation in metal-organic frameworks for enhanced adsorption performance of ReO4-/TcO4

Qing-Hua Hu; You-Gan Wang; Xin Gao; Yu-Zhen Shi; Sen Lin; Ru-Ping Liang; Jian-Ding Qiu

doi:10.1016/j.jhazmat.2023.130744

Halogen microregulation in metal-organic frameworks for enhanced adsorption performance of ReO₄^-/TcO₄

J Hazard Mater. 2023 Mar 15:446:130744. doi: 10.1016/j.jhazmat.2023.130744. Epub 2023 Jan 7.

Authors

Qing-Hua Hu¹, You-Gan Wang¹, Xin Gao¹, Yu-Zhen Shi¹, Sen Lin¹, Ru-Ping Liang², Jian-Ding Qiu³

Affiliations

¹ School of Chemistry and Chemical Engineering, Nanchang University, Nanchang 330031, China.
² School of Chemistry and Chemical Engineering, Nanchang University, Nanchang 330031, China. Electronic address: rpliang@ncu.edu.cn.
³ School of Chemistry and Chemical Engineering, Nanchang University, Nanchang 330031, China; State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang 330013, China. Electronic address: jdqiu@ncu.edu.cn.

PMID: 36630874
DOI: 10.1016/j.jhazmat.2023.130744

Abstract

Effective and selective removal of ⁹⁹TcO₄^-, one of the most nuisance radionuclides in nuclear waste, is highly desirable but remains a significant challenge. Herein, two isostructural MOFs, NCU-3-X (X = Cl, Br) were constructed by ZnX₂ coordinated to nitrogen-containing neutral ligand tri(4-(1H-imidazole-1-l) phenyl) amine for efficient adsorption ReO₄^-/TcO₄^-. Owning to the twofold interpenetrating structure, both of them exhibit strong alkaline resistance. Consequently, NCU-3-Br exhibited superior adsorption performances with a maximum capacity as high as 483 mg/g, which is 2.23 times larger than that of NCU-3-Cl. The primary reasons accounting for the enhanced adsorption performances of NCU-3-Br are that compared to chlorine atoms, the smaller electronegativity of bromine atoms as halogen bonds donor can facilitate the formation of σ-holes, enhance positively charged skeleton, and reduce the adsorption energy associated with ReO₄^-/TcO₄^-. In addition, the one-dimensional hydrophobic channels in the NCU-3-Br framework enable NCU-3-Br to have highly selective toward ReO₄^-, which has a low relative charge density against interfering ions. The SRS simulation removal experiment further confirmed the excellent adsorption capacity of NCU-3-Br to ReO₄^-/TcO₄^-. This work illustrated that the halogenated new strategy incorporated different halogen atoms into MOF skeletons can dramatically modulate the adsorption performances for ReO₄^-/TcO₄^-.

Keywords: Adsorption; Halogen bond; Metal-organic framework; Nuclear wastes; ReO(4)(-)/TcO(4)(-).