物理化学学报 >> 2013, Vol. 29 >> Issue (11): 2422-2428.doi: 10.3866/PKU.WHXB201309021

催化和表面科学 上一篇    下一篇

磺酸功能化金属-有机骨架吸附脱氮性能

王朝阳, 李钢, 孙志国   

  1. 大连理工大学化工学院, 精细化工国家重点实验室, 辽宁 大连 116024
  • 收稿日期:2013-06-12 修回日期:2013-09-02 发布日期:2013-10-30
  • 通讯作者: 李钢 E-mail:liganghg@dlut.edu.cn
  • 基金资助:

    国家重点基础研究发展计划项目(973)(2011CB201301)资助

Denitrogenation through Adsorption to Sulfonated Metal-Organic Frameworks

WANG Zhao-Yang, LI Gang, SUN Zhi-Guo   

  1. State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, Liaoning Province, P. R. China
  • Received:2013-06-12 Revised:2013-09-02 Published:2013-10-30
  • Contact: LI Gang E-mail:liganghg@dlut.edu.cn
  • Supported by:

    The project was supported by the National Key Basic Research Program of China (973) (2011CB201301).

摘要:

以硝基甲烷为溶剂,采用三氟甲磺酸酐(Tf2O)和浓硫酸对金属有机骨架材料MIL-101(Cr){Cr3F(H2O)2O[(O2C)-C6H4-(CO2)]3·nH2O(n~25)}进行磺酸功能化修饰,使其孔壁配体上形成磺酸基团.通过改变MIL-101(Cr)、Tf2O和浓硫酸的摩尔配比,得到含有不同磺酸基团数量的S-MIL-101(Cr),对磺化后的材料进行了X射线衍射(XRD)、傅里叶变换红外(FTIR)、氮气物理吸附、酸碱电位滴定以及热重分析(TGA)表征.结果表明,磺酸功能化后MIL-101(Cr)的孔道结构仍然保持,比表面积和孔径有所下降,表面磺酸基团的数量根据磺化程度的不同从0.21到0.42mmol·g-1不等.将磺酸功能化后的MIL-101(Cr)用于液体燃料的吸附脱氮,发现磺酸功能化能够增强MIL-101(Cr)与含氮化合物的相互作用,有利于其对碱性氮化物的吸附脱除.相对于未经磺化的样品,按照摩尔配比n(MIL-101(Cr)):n(H2SO4):n(Tf2O)=1:3:4.5反应得到的磺酸功能化MIL-101(Cr)对喹啉和吲哚的吸附量提高较大,其对喹啉和吲哚的Langmuir最大吸附量分别提高了12.2%和6.3%.通过乙醇洗涤,吸附剂可再生,经过三次再生之后的吸附剂对模拟燃料中含氮化合物的吸附量没有明显的降低.

关键词: 金属有机骨架, 磺酸功能化, 吸附脱氮, Langmuir吸附, 吸附等温线

Abstract:

Sulfonic acid functionalized MIL-101(Cr) (S-MIL-101(Cr)) are obtained by sulfonation of MIL-101(Cr) (Cr3F(H2O)2O[(O2C)-C6H4-(CO2)]3·nH2O (n~25)) using triflic anhydride and sulfuric acid. The amount of sulfonic groups in the framework can be controlled by changing the molar ratio of MIL-101(Cr), triflic anhydride, and sulfuric acid. The sulfonated samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, nitrogen physical adsorption/desorption, acid-base potentiometric titration, and thermogravimetric analysis (TGA). The results show that the sulfonated samples retain the general structure of MIL-101(Cr), but the specific areas and pore diameters decrease. The sulfonated samples formed with between 0.21 and 0.42 mmol·g-1 of sulfonic acid groups. The adsorptive denitrogenation of a model fuel by different S-MIL-101(Cr) samples was investigated in batch adsorption experiments. Sulfonation can strengthen the interactions between nitrogen-containing compounds (NCCs) and the adsorbent. The sample obtained using a molar ratio of n(MIL-101(Cr)):n(H2SO4):n(Tf2O)=1:3:4.5 had the largest adsorption capacity for quinoline and indole. Compared with the bare MIL-101(Cr), this sulfonated material showed enhancement of the maximum adsorption capacity by 12.2% and 6.3% for quinoline and indole, respectively. Regeneration of the used adsorbent was conducted by washing with ethanol, and the adsorptive capacity for NCCs from the model-fuel showed no obvious decrease after three cycles of use.

Key words: Metal-organic framework, Sulfoacid functionalization, Adsorptive denitrogenation, Langmuir adsorption, Adsorption isothermal

MSC2000: 

  • O647