Highly selective cesium(I) capture under acidic conditions by a layered sulfide

Jun-Hao Tang,Wei-An Li,Xi Zeng,Xiao-Ying Huang,Ying-Chen Peng,Wen Ma,Ji-Long Li,Jian-Ce Jin,Tian-Tian Lv,Mei-Ling Feng

doi:10.1038/s41467-022-28217-8

Abstract

Radiocesium remediation is desirable for ecological protection, human health and sustainable development of nuclear energy. Effective capture of Cs+ from acidic solutions is still challenging, mainly due to the low stability of the adsorbing materials and the competitive adsorption of protons. Herein, the rapid and highly selective capture of Cs+ from strongly acidic solutions is achieved by a robust K+-directed layered metal sulfide KInSnS4 (InSnS-1) that exhibits excellent acid and radiation resistance. InSnS-1 possesses high adsorption capacity for Cs+ and can serve as the stationary phase in ion exchange columns to effectively remove Cs+ from neutral and acidic solutions. The adsorption of Cs+ and H3O+ is monitored by single-crystal structure analysis, and thus the underlying mechanism of selective Cs+ capture from acidic solutions is elucidated at the molecular level.

Highlights

Radiocesium remediation is desirable for ecological protection, human health and sustainable development of nuclear energy
A common feature of both compounds is the high coordination number of metal ions in the framework, which is the highest among the reported metal sulfide ion exchangers[8,17,22]
A robust K+-directed layered metal sulfide InSnS-1 has been synthesized by a simple solid-phase method according to the following reaction formula (Eq (1)): KInS2 þ Sn þ 2 S 7À5À0ÀCÀ;4Àd!ays KInSnS4 ð1Þ

Summary

Introduction

Radiocesium remediation is desirable for ecological protection, human health and sustainable development of nuclear energy. InSnS-1 possesses high adsorption capacity for Cs+ and can serve as the stationary phase in ion exchange columns to effectively remove Cs+ from neutral and acidic solutions. Ion exchange is considered an ideal method for controlling radioactive contamination due to its simplicity of operation, high efficiency, and lack of secondary contamination[11], the development of stable and highly selective ion exchangers for the efficient capture of Cs+ in acidic solutions still remains a great challenge. Materials that can effectively remove Cs+ ions under extremely acidic condition are still very limited, exemplified mainly by ammonium phosphomolybdate and its complexes or cupric aromatic crown ether-modified silyl compounds[13–16]. It is of vital significance to develop acid-tolerant ion exchangers that can selectively capture Cs+ from strongly acidic solutions for radioactive liquid waste treatment and to clarify the mechanism of Cs+ removal for revealing the structure–function relationship

Methods

Results

Conclusion