高等学校化学学报 ›› 2016, Vol. 37 ›› Issue (10): 1856.doi: 10.7503/cjcu20160263

• 物理化学 • 上一篇    下一篇

ZIF-8的合成、 表征及正己烷吸附性能

刘克峰, 任丹妮, 孙辉(), 沈本贤, 刘纪昌   

  1. 华东理工大学石油加工研究所, 上海 200237
  • 收稿日期:2016-04-20 出版日期:2016-10-10 发布日期:2016-09-18
  • 作者简介:联系人简介: 孙 辉, 男, 博士, 副教授, 主要从事高性能多孔材料的合成及吸附性能研究. E-mail:sunhui@ecust.edu.cn
  • 基金资助:
    上海市自然科学基金(批准号: 16ZR1408100)资助

Synthesis, Characterization and n-Hexane Adsorption Performance of ZIF-8

LIU Kefeng, REN Danni, SUN Hui*(), SHEN Benxian, LIU Jichang   

  1. Petroleum Processing Research Center, East China University of Science and Technology, Shanghai 200237, China
  • Received:2016-04-20 Online:2016-10-10 Published:2016-09-18
  • Contact: SUN Hui E-mail:sunhui@ecust.edu.cn
  • Supported by:
    † Supported by the Natural Science Foundation of Shanghai, China(No.16ZR1408100)

摘要:

以甲醇为溶剂, 硝酸锌六水合物为锌源, 2-甲基咪唑为有机配体, 通过溶剂热法合成了金属有机骨架材料ZIF-8; 采用X射线衍射(XRD)、 氮气吸附、 热重-差热分析(TG-DSC)和扫描电子显微镜(SEM)等方法对ZIF-8样品进行了表征; 研究了正己烷在ZIF-8上的液相吸附动力学和动态选择性吸附性能. 结果表明, 合成的ZIF-8晶体具有方钠石结构, 结晶度较高, 孔结构主要为0.37~1.10 nm的微孔, BET比表面积为1836 m2/g, 孔体积为0.65 cm3/g. TG-DSC和高温原位XRD分析结果表明, 合成的ZIF-8具有良好的热稳定性能. 283~313 K时, 正己烷在ZIF-8上液相吸附的扩散系数为(2.53~8.88)×10-12 cm2/s, 扩散活化能为31.11 kJ/mol; 308 K时, ZIF-8对正己烷的动态饱和吸附量为187.3 mg/g, 由吸附穿透曲线计算得出Thomas速率常数为2.17×10-3 mL·min-1·mg-1. 与5A分子筛相比, ZIF-8对正己烷的吸附容量高出约1倍, 液相吸附表观扩散时间常数高出约70%.

关键词: ZIF-8, 正己烷, 吸附动力学, 吸附容量, 动态吸附

Abstract:

The zeolitic imidazolate framework ZIF-8 was synthesized through a solvothermal process employing methanol as the solvent, zinc nitrate hexahydrate and 2-methylimidazole as zinc source and organic ligand, respectively. The products were characterized by means of XRD, N2 adsorption, TG-DSC and SEM. In addition, selective adsorption performance for n-hexane on ZIF-8 was investigated. It is indicated that synthesized ZIF-8 has the sodalite crystal structure and a high crystallinity. From the N2 adsorption results, ZIF-8 product has a pore size range of 0.4—1.1 nm, BET specific surface area of 1836 m2/g and pore volume of 0.65 cm3/g. Both TG-DSC and high-temperature in situ XRD analyses suggest its excellent thermal stability. As the temperature increases from 283 to 313 K, the diffusion coefficient for n-hexane adsorption on ZIF-8 varies from 2.53×10-12 to 8.88×10-12 cm2/s and diffusion activation energy is evaluated to be 31.11 kJ/mol. At 308 K, the dynamic adsorption capacity and Thomas adsorption rate constant for n-hexane on ZIF-8 are 187.3 mg/g and 2.17×10-3 mL·min-1·mg-1, respectively. As compared to 5A molecule sieve, ZIF-8 displays around 100% higher adsorption capacity and almost 70% faster diffusion rate.

Key words: ZIF-8, n-Hexane, Adsorption kinetics, Adsorption capacity, Dynamic adsorption

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