CIESC Journal ›› 2022, Vol. 73 ›› Issue (10): 4507-4517.DOI: 10.11949/0438-1157.20220531

• Separation engineering • Previous Articles     Next Articles

Molecular simulation study on adsorption and separation of H2/He mixtures by M-MOF-74

Yujie WANG1,2(), Shenhui LI2, Zhiping ZHAO2()   

  1. 1.Sinopec Beijing Research Institute of Chemical Industry, Beijing 100013, China
    2.School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 102488, China
  • Received:2022-04-13 Revised:2022-08-08 Online:2022-11-02 Published:2022-10-05
  • Contact: Zhiping ZHAO

M-MOF-74吸附分离H2/He混合物的分子模拟研究

王玉杰1,2(), 李申辉2, 赵之平2()   

  1. 1.中国石化北京化工研究院,北京 100013
    2.北京理工大学化学与化工学院,北京 102488
  • 通讯作者: 赵之平
  • 作者简介:王玉杰(1980—),女,博士,高级工程师,wangyuj.bjhy@sinopec.com
  • 基金资助:
    国家自然科学基金重点项目(21736001);国家重点研发计划项目(2021YFC2101203)

Abstract:

In order to explore whether the organometallic framework MOF-74 can be used as an excellent solid adsorbent to separate H2 in H2/He mixture and achieve the purpose of purifying He, the adsorption performance and adsorption mechanism of H2, He and H2/He mixture on M-MOF-74 (M=Mg, Co, Ni, Cu, Zn) were studied by molecular simulation. The results show that the selectivity of pure H2 to pure He on Ni-MOF-74 is 6.58 under the conditions of 1 bar pressure and 25 °C. The amount of H2 adsorbed on Mg-MOF-74 is the largest (0.19 mmol·cm-3) in the same condition, which is 6.46 times of He. When the concentration of the H2/He mixture was changed, it had no great effect on its adsorption separation factor on M-MOF-74, indicating that the concentration change would not affect the ability of the adsorption sites on M-MOF-74 to accommodate H2 and He. The adsorption site and adsorption heat analysis showed that the metal ion unsaturated sites on MOF-74 could significantly enhance its adsorption capacity for H2. The results provide a theoretical basis for judging whether M-MOF-74 has the potential to separate H2/He mixtures and quantitatively analyzing the contribution of metal unsaturated sites of MOFs to the separation of H2/He mixtures.

Key words: MOF-74, H2/He mixture, adsorbents, adsorption, molecular simulation

摘要:

为了探究有机金属框架MOF-74能否作为一种优良的固体吸附剂,分离H2/He混合物中H2,并达到提纯He的目的,采用分子模拟的手段研究了H2、He及H2/He混合物在M-MOF-74(M=Mg、Co、Ni、Cu、Zn)上的吸附性能及吸附机理。结果表明,在1 bar(1 bar=105 Pa)压力和25℃条件下,纯H2对纯He在Ni-MOF-74上的选择性达6.58,而Mg-MOF-74对H2的吸附量最大,其值为0.19 mmol·cm-3,为He吸附量的6.46倍。当H2/He混合物的浓度发生变化时,对其在M-MOF-74上的吸附分离因子没有较大影响,说明浓度变化不会影响M-MOF-74上吸附位点容纳H2和He的能力。吸附位点和吸附热分析表明,MOF-74上的金属离子未饱和位点能够显著增强其对H2的吸附能力。其结果对判断M-MOF-74是否具有分离H2/He混合物的潜力,以及定量分析MOFs金属未饱和位点对H2/He混合物分离的贡献提供了一定的理论基础。

关键词: MOF-74, H2/He混合物, 吸附剂, 吸附, 分子模拟

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