物理化学学报 >> 2015, Vol. 31 >> Issue (4): 660-666.doi: 10.3866/PKU.WHXB201501291

理论与计算化学 上一篇    下一篇

石墨烯/纳米管复合结构吸附分离CO2/CH4混合物的分子模拟

雷广平, 刘朝, 解辉   

  1. 重庆大学低品位能源利用技术及系统教育部重点实验室, 重庆400030
  • 收稿日期:2014-09-24 修回日期:2015-01-28 发布日期:2015-04-03
  • 通讯作者: 刘朝 E-mail:liuchao@cqu.edu.cn
  • 基金资助:

    国家自然科学基金(51206195)资助项目

Molecular Simulation of Adsorption and Separation Performances for CO2/CH4 Mixtures in Graphene/Nanotube Hybrid Structures

LEI Guang-Ping, LIU Chao, XIE Hui   

  1. Key Laboratory of Low-Grade Energy Utilization Technologies and Systems of Ministry of Education, Chongqing University, Chongqing 400030, P. R. China
  • Received:2014-09-24 Revised:2015-01-28 Published:2015-04-03
  • Contact: LIU Chao E-mail:liuchao@cqu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (51206195).

摘要:

采用巨正则蒙特卡洛(GCMC)及分子动力学(MD)方法探讨了石墨烯/碳纳米管三维骨架结构(GNHS)对等摩尔CO2/CH4二元混合物的吸附分离性能. 模拟结果表明CO2比CH4更易吸附于GNHS中, GNHS与(6, 6)SWCNT (单壁碳纳米管)相比具有更高的分离性能. 随着温度升高, CO2的吸附量快速降低, 而CH4的吸附量则呈现出先升高后降低的趋势. 最后采用分子动力学方法计算了CO2与CH4的自扩散系数及停留时间等动力学相关参数, 发现CO2在GNHS内扩散的阻力更大. 而各组分在吸附剂外部吸附层内的扩散过程对混合物的分离也存在一定影响.

关键词: 石墨烯/碳纳米管三维骨架结构, 吸附等温线, 停留时间, 吸附选择性, 吸附系数

Abstract:

The adsorption and separation behaviors of CO2 and CH4 binary mixture in graphene/nanotube hybrid structures (GNHSs) are investigated by grand canonical Monte Carlo (GCMC) combined with molecular dynamics (MD) simulations. CO2 is preferentially adsorbed in the adsorbents. Compared with a (6, 6) SWCNT (single walled carbon nanotube), GNHSs show improved separation performance. As the temperature rises, the loading of CO2 reduces rapidly while the loading of CH4 first increases before being reduced. Finally, the kinetic parameters of CO2 and CH4, such as self-diffusivity and residence time, are calculated by MD simulation. The CO2 molecules diffusing in the GNHS need to overcome a higher barrier relative to that for CH4. The diffusion of the two components in the adsorption layer outside of adsorbent also influences the separation of the mixture.

Key words: Graphene/nanotube hybrid structure, Adsorption isotherm, Residence time, Adsorption selectivity, Adsorption coefficient

MSC2000: 

  • O647