化学学报 ›› 2014, Vol. 72 ›› Issue (12): 1228-1232.DOI: 10.6023/A14090632 上一篇    下一篇

研究论文

基于尺寸识别和离子交换实现有机染料分离的一例阴离子型MOF

何燕萍, 谭衍曦, 张健   

  1. 结构化学国家重点实验室 中国科学院福建物质结构研究所 福州 350002
  • 收稿日期:2014-09-05 出版日期:2014-12-14 发布日期:2014-10-30
  • 通讯作者: 张健 E-mail:zhj@fjirsm.ac.cn
  • 基金资助:

    项目受973计划(Nos.2011CB932504,2012CB821705)和国家自然科学基金(Nos.21221001,21403235)资助.

An Anionic MOF for Separation of Organic Dyes via Cationic-Exchange and Size-Exclusion

He Yanping, Tan Yanxi, Zhang Jian   

  1. State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002
  • Received:2014-09-05 Online:2014-12-14 Published:2014-10-30
  • Supported by:

    Project supported by the 973 Program (Nos. 2011CB932504 and 2012CB821705) and the National Natural Science Foundation of China (Nos. 21221001, 21403235).

在溶剂热的条件下, 利用5-氨基间苯二甲酸(H2aip)配体和硝酸铟[In(NO3)3·5H2O]定向构筑了一例二维结构的阴离子型金属有机框架材料, {(Me2NH2)·[In(aip)2]}·xG (1, G=客体分子). 采用X射线单晶衍射、热分析仪(TGA)和X射线粉末衍射(PXRD)等方法对该化合物进行了结构表征. 经过活化后样品1-ht几乎不吸附氮气, 但却能有效地吸附氢气和二氧化碳. 此外, 化合物1还可以通过离子交换和尺寸识别的方式来吸附阳离子亚甲基蓝(MB)染料, 而很难吸附阴离子甲基橙(MO)染料和分子尺寸更大的阳离子罗丹明B (RhB)染料, 实现水相中MB/MO和MB/RhB的选择性分离.

关键词: 金属-有机框架材料, 晶体结构, 有机染料, 吸附, 分离

By employing the 5-aminoisophthalic acid (H2aip) ligand to assemble with In3+ ion, a two-dimensional (2D) anionic metal-organic framework (MOF), namely {(Me2NH2)·[In(aip)2]}·xG (1, G=guest), was solvothermally synthesized. In(NO3)3·5H2O (38 mg, 0.1 mmol) and H2aip (45 mg, 0.25 mmol) are added to a mixed solvent of DMF/EtOH/H2O (V:V:V=2:2:1), and then the solution was placed in a small vial. After ultrasonic diffusion for 2 min, it is heated at 120 ℃ for 2 d to obtain yellowish sheet crystals (yield 75% based on H2aip). 1 can be stable under different organic solvent and water. Single crystal diffraction is used to characterize its structure. 1 crystallizes in P-1 space group and presents a 2D sql net. There is weak hydrogen bonding interaction between layers, which effectively prevents the relative motion of the frameworks. The infinite layers further pack into a 3D framework in an AB fashion, thus generating some channels in every direction. Thermogravimetric analysis (TGA) and X-ray powder diffraction (PXRD) are used to measure its thermal stability and purity. The framework can be stable up to 350 ℃ after the guest molecular removed. For gas adsorption studies, 1 was heated at 150 ℃ for 6 h under a vacuum, and then the desolvated solid 1-ht is obtained. Gas sorption measurements indicate that 1-ht can hardly adsorb N2 (0.8 cm3·g-1), but except for H2 (91.2 cm3·g-1) and CO2 (44.9 cm3·g-1), which shows potential applications in CO2/N2 separation at 273 K and 101 kPa. In addition, based on ion-exchange and size-exclusion effect, compound 1 can rapidly adsorb cationic methylene blue (MB) from water in 2 h, but except for anionic methyl orange (MO) and much larger Rhodamine B (RhB). Based on these characters, compound 1 can effectively separate MB over MO and RhB in their mixed water solution. This is a promising application for MOFs in this field. However, only a few MOFs have been investigated to adsorb organic dyes, and the selective separation of mixed dyes in water by MOFs remains rarely explored to date.

Key words: metal-organic framework, structure, organic dye, adsorption, separation