Decorating Channel Walls in Metal–Organic Frameworks with Crown Ethers for Efficient and Selective Separation of Radioactive Strontium(II)

Abstract

Nuclear accidents and the improper disposal of nuclear wastes have led to serious environmental pollution. The rational design of adsorbents for the highly efficient separation of strontium(II) is essential in treating nuclear waste and recovering radioactive strontium resources. Metal‐organic frameworks (MOFs) are potential materials for the separation of aqueous metal ions owing to their designable structure and tunable functionality. Herein, a novel 3D MOF material MOF‐18Cr6, in which 1D channels were formed using 18‐crown‐6‐ether‐containing ligands as channel walls, was fabricated for strontium(II) separation. In contrast to traditional MOFs designed by grafting functional groups in the framework pores, MOF‐18Cr6 possesses regular 18‐crown‐6‐ether cavities on the channel walls, which not only can transport and intake strontium(II) via the channels, but also prevent blockage of the channels after the binding of strontium(II). Consequently, the functional sites were fully utilized to achieve a high strontium(II) removal rate of 99.73% in simulated nuclear wastewater. This study fabricates a highly promising adsorbent for the separation of aqueous radioactive strontium(II), and more importantly, can provide a new strategy for the rational design of high‐performance MOF adsorbents for separating target substances from complex aqueous environments.

Engineering Cryptand-like Coordination Sites in Multisite Metal Acyl-Organic Cages for Specific Recognition and Deep Purification of Radioactive Strontium(II)

“…Inspired by the selective recognition capabilities of traditional macrocyclic crown ethers towards various metal ions, i.e. strontium(II), [52][53][54] indium(III), [55][56][57] plutonium(V), 58 and et al, the internal functional groups may render UOC to behave as a metal receptor for the recognition of metal ions by providing an appropriate coordination environment.…”