摘要
^(137)Cs具有强放射性和较长半衰期,一旦从核废液中泄露将对人类健康和环境造成很大危害.由于^(137)Cs^(+)的高溶解性、易迁移性和废液中干扰离子的影响,从复杂的放射性废液中有效去除^(137)Cs^(+)仍然是一个挑战.本研究通过溶剂热法合成了两例新的三维微孔镧系金属-有机框架化合物(Me_(2)NH_(2))_(0.5)(H_(3)O)_(0.25)Na_(0.25)Ln(OH)(stp)·0.25H_(2)O(FJSM-LnMOF;Ln=Eu,Tb;H_(3)stp=2-磺酸基对苯二甲酸),它们具有良好的水稳定性和一定的耐酸碱性.FJSM-EuMOF和FJSM-TbMOF对Cs^(+)离子吸附具有快速的动力学和高的吸附量(qm^(Cs)分别为229.25和211.28 mg/g).它们对Cs^(+)离子具有良好的选择性(Kd^(Cs)值高达2.18×10^(3)mL/g).即使在Na^(+),K^(+),Mg^(2+),Ca^(2+)离子干扰的情况下,它们仍然表现出对Cs^(+)离子的选择性吸附性能.我们成功获得了Cs^(+)吸附产物的单晶结构,通过单晶结构分析结合X射线光电子能谱(XPS),红外(IR),扫描电镜能量色散谱(EDS)和元素分析(EA)等多种表征方法,证实了FJSM-EuMOF对Cs^(+)离子的吸附为离子交换的机理.结果表明,FJSM-EuMOF对Cs^(+)离子的高效吸附主要源于镧系金属-有机阴离子框架中有机配体上的COO^(-)和SO^(3)^(-)官能团对Cs^(+)离子强的作用力以及通道内存在易交换的[Me_(2)NH_(2)]^(+)阳离子和[H_(3)O]^(+)离子.这项工作表明,镧系金属-有机框架化合物在放射性铯的修复中具有潜在的应用价值.
^(137)Cs 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 ^(137)Cs^(+)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(Me_(2)NH_(2))_(0.5)(H_(3)O)_(0.25)Na_(0.25)Ln(OH)(stp)·0.25H_(2)O(FJSM-LnMOF;Ln=Eu,Tb;H_(3)stp=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 qm^(Cs) of FJSM-EuMOF and FJSM-TbMOF are 229.25 and 211.28 mg/g,respectively).They have good selectivity for Cs^(+)ions(Kd^(Cs) value up to 2.18×10^(3) mL/g).Even in the presence of interfering Na^(+),K^(+),Mg^(2+),Ca^(2+)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 SO_(3)^(-) functional groups from organic ligands and Cs^(+)ions,and the presence of easily exchangeable[Me_(2)NH_(2)]^(+)cations and[H_(3)O]^(+)located in the channels.This work indicates the potential application of lanthanide metal-organic frameworks in the remediation of radioactive cesium.
作者
吕天天
马文
詹冬笋
邹燕敏
李继龙
冯美玲
黄小荥
Lü Tiantian;Ma Wen;Zhan Dongsun;Zou Yanmin;Li Jilong;Feng Meiling;Huang Xiaoying(College of Material Science and Engineering,North University of China,Taiyuan 030051;State Key Laboratory of Structural Chemistry,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences,Fuzhou 350002)
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2022年第5期640-659,共20页
Acta Chimica Sinica
基金
国家自然科学基金(Nos.U21A20296,22076185,21771183)
福建省自然科学基金(No.2020J06033)资助项目
关键词
镧系金属-有机框架
晶体结构
去除铯
离子交换
动力学
吸附量
选择性
lanthanide-organic framework
crystal structure
removal of cesium
adsorption mechanism
ion exchange
kinetics
adsorption capacity
selectivity
作者简介
冯美玲,E-mail:fml@fjirsm.ac.cn,Tel.:0591-63173146,Fax:0591-63173146.
