Chinese Journal of Applied Chemistry

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Molecular Dynamics Simulation of Tip Functionalized Carbon Nanotube Membrane for Li+/Mg2+ Separation

YANG Dengfeng1,2, LIU Qingzhi2, LI Hongman1, GAO Congjie1*   

  1. (1.College of Chemistry and Chemical Engineering,Ocean University of China,Qingdao 266100,China;
    2.Chemistry and Pharmacy Science College,Qingdao Agricultural University,Qingdao 266109,China)
  • Received:2013-12-06 Revised:2014-04-06 Online:2014-10-09 Published:2014-10-09
  • Contact: Gao Congjie
  • About author:Corresponding author: GAO Congjie, professor; Tel/Fax: 0532-66782481; Email:; Research interests: Synthesis and properties of seawater reverse osmosis membrane.

Abstract: Using molecular dynamics simulations, we studied the transport of Li+ and Mg2+ through membrane formed from armchair type (10,10) carbon nanotubes whose top rims were modified with a range of different charged functional groups including COO- and NH+3 under 80 MPa hydrostatic pressure, and investigated the potential of mean force, conductance and density distributions of ions in the carbon nanotubes. The results show that appropriately modified (10,10) carbon nanotubes can effectively extract Li+. The bound and rejection effects produced by electrostatic interaction between charged groups and ions reduce the conductance of ions in the tubes. Mg2+ can permeate the functionalized carbon nanotubes and Li+ are also completely blocked with the addition of 8COO- and 4NH+3. The maximum conductance of Li+ are found in carbon nanotubes modified with 1COO- and 1NH+3 functional groups which can most effectively separate Li+ and Mg2+. Therefore, through addition of specific charged modified groups, the separation performance of large diameter carbon nanotube to Li+ and Mg2+ can be effectively improved. Charge properties and the quantity of modification groups greatly affect the separation effects.

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