碳纳米管膜分离Li^+/Mg^(2+)的分子动力学模拟

Molecular Dynamics Simulation of Carbon Nanotube Membrane Separating Li^+/Mg^(2+)

采用"扶手椅"型碳纳米管建立了连续的碳纳米管膜模型,利用分子动力学模拟方法研究了Li+和Mg2+在膜中的传导行为.模拟研究了不同管径的碳纳米管CNTs(7,7),(8,8),(9,9),(10,10),(11,11)对Li+和Mg2+的通透性,检测了两种离子进入管内时的平均力势,探索了两种离子在碳纳米管内的径向、轴向密度分布,观测了个别离子在管内的运动轨迹.结果表明,模拟中CNTs(9,9)用于有效分离Li+和Mg2+的效果较好.管径不同,导致Li+和Mg2+通量不同,平均力势(PMF)差值不同,同时离子的轨迹和径向、轴向密度分布也有所差异.总之,碳纳米管是一种可将Li+和Mg2+分离的潜在材料.

Armchair-type carbon nanotubes（CNTs） were used to construct a continuous nanotube membrane model. The conductivity behaviors of Li^＋ and Mg^2＋ in the nanotubes were examined via molecular dynamics simulation. In the simulation, the permeability of Li^＋ and Mg^2＋ in CNTs （ 7,7 ）, （ 8,8 ）, （ 9,9 ）, （ 10,10 ）, （ 11,11 ） with different diameters were investigated. The potentials of mean force （PMF） for ions entering the nanotubes, radial and axial ions density distributions, and the trajectories of individual ions transporting in tubes were explored. The results indicate that CNTs （9,9） is effective in separating Li^＋ and Mg^2＋ in the simu- lation. With different nanotube diameters, the conductance, PMF difference, trajectories, radial and axial density distributions of Li^＋ and Mg^2＋ are different. In short, the carbon nanotube is a potential material for separating Li^＋ and Mg^2＋.