Acta Chimica Sinica ›› 2022, Vol. 80 ›› Issue (5): 640-646.DOI: 10.6023/A21120614 Previous Articles     Next Articles

Special Issue: 中国科学院青年创新促进会合辑



吕天天a,b, 马文b, 詹冬笋b, 邹燕敏b, 李继龙b, 冯美玲b,*(), 黄小荥b   

  1. a 中北大学材料科学与工程学院 太原 030051
    b 中国科学院福建物质结构研究所 结构化学国家重点实验室 福州 350002
  • 投稿日期:2021-12-31 发布日期:2022-05-31
  • 通讯作者: 冯美玲
  • 作者简介:
  • 基金资助:
    国家自然科学基金(U21A20296); 国家自然科学基金(22076185); 国家自然科学基金(21771183); 福建省自然科学基金(2020J06033)

Two New Three-Dimensional Lanthanide Metal-organic Frameworks for the Highly Efficient Removal of Cs+ Ions

Tiantian Lüa,b, Wen Mab, Dongsun Zhanb, Yanmin Zoub, Jilong Lib, Meiling Fengb(), Xiaoying Huangb   

  1. a College of Material Science and Engineering, North University of China, Taiyuan 030051
    b State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002
  • Received:2021-12-31 Published:2022-05-31
  • Contact: Meiling Feng
  • About author:
    Dedicated to the 10th anniversary of the Youth Innovation Promotion Association, CAS.
  • Supported by:
    National Natural Science Foundation of China(U21A20296); National Natural Science Foundation of China(22076185); National Natural Science Foundation of China(21771183); Natural Science Foundation of Fujian Province(2020J06033)

137Cs has the strong radioactivity and long half-life. In the event of leaking, it will pose a great danger to human health and the environment. The effective removal of 137Cs+ from complex radioactive waste streams remains a challenge due to its high solubility, easy migration and the influence of interfering ions in the waste streams. In this study, two new three-dimensional microporous lanthanide metal-organic framework compounds (Me2NH2)0.5(H3O)0.25Na0.25Ln(OH)(stp)• 0.25H2O (FJSM-LnMOF; Ln=Eu, Tb; H3stp=2-sulfonic acid terephthalic acid) are synthesized by the solvothermal method, which have the good water stability and acid-base resistance. The adsorption performance of FJSM-LnMOFs for Cs+ are tested with solid-liquid ratio of 1∶1 under stirring at room temperature for 8 h. The adsorption kinetics of FJSM-EuMOF for Cs+ are tested with low-concentration Cs+ solution. FJSM-LnMOFs show fast kinetics and high adsorption capacities of Cs+ ions (the maximum adsorption capacities qmCs of FJSM-EuMOF and FJSM-TbMOF are 229.25 and 211.28 mg/g, respectively). They have good selectivity for Cs+ ions (KdCs value up to 2.18×103 mL/g). Even in the presence of interfering Na+, K+, Mg2+, Ca2+ ions, they still show selective adsorption performance for Cs+ ions. Impressively, we successfully obtain the single crystal structure of Cs+-absorbed product by soaking FJSM-EuMOF crystals in 20,000 mg/L Cs+ solution, which confirms that the adsorption mechanism of Cs+ ions is ion exchange by the means of single crystal structure analysis combined with various characterization methods including X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR), energy dispersion spectrum (EDS), elemental analysis (EA). The results indicate that the highly efficient Cs+ adsorption of FJSM-LnMOF mainly originates from the strong interactions between COO and $\text{SO}_{3}^{}$ functional groups from organic ligands and Cs+ ions, and the presence of easily exchangeable [Me2NH2]+ cations and [H3O]+ located in the channels. This work indicates the potential application of lanthanide metal-organic frameworks in the remediation of radioactive cesium.

Key words: lanthanide-organic framework, crystal structure, removal of cesium, adsorption mechanism, ion exchange, kinetics, adsorption capacity, selectivity