Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (11): 2000-2008.doi: 10.3866/PKU.WHXB201408291

• THEORETICAL AND COMPUTATIONAL CHEMISTRY • Previous Articles     Next Articles

Molecular Simulations of the Purification of Toxic Benzene Gas on Single-Walled Carbon Nanotubes

PENG Xuan   

  1. College of Information Science and Technology, Beijing University of Chemical Technology, Beijing 100029, P. R. China
  • Received:2014-06-04 Revised:2014-08-29 Published:2014-10-30
  • Contact: PENG Xuan E-mail:pengxuan@mail.buct.edu.cn,pengxuan@126.com
  • Supported by:

    The project was supported by the Open Project of State Key Laboratory of Chemical Engineering, China (SKL-Che-12C01).

Abstract:

Grand canonical ensemble Monte Carlo (GCMC) simulations were performed to investigate the purification of benzene from air by single-walled carbon nanotubes (SWNTs). It was found that (20,20) SWNT with a large diameter is suitable to adsorb pure benzene. For the removal of benzene in air, the minimum and maximum selectivities were observed for the (12,12) SWNT at 4.0 MPa and the (18,18) SWNT at 0.1 MPa, respectively. To obtain deep insight into the unusual behavior, we analyzed the local density profiles, snapshots, and probability profiles of N2-O2-C6H6 mixtures. The results showed that the (18,18) SWNT was entirely occupied by benzene molecules, while, for the (12,12) SWNT, N2 andwere prone to appear in the interstices between tubes, instead of inside tubes, because of stronger adsorbate-adsorbent interactions. Additionally, we calculated the orientation order parameters of the adsorbates. The results suggested that benzene molecules prefer lying nearly flat on the pore surface, while N2 and O2 molecules orient parallel to the pore axis. Finally, the effects of temperature and concentration on the selectivity of benzene were investigated. We found that with increasing temperature the selectivity in large pores decreased more evidently than that in small pores. By contrast, the concentration plays a more important role in affecting the selectivity in small pores.

Key words: Grand canonical ensemble Monte Carlo, Adsorption, Separation, Benzene, Air, Carbon nanotube

MSC2000: 

  • O647