移动式纳米碳管膜在盐水分离中的模拟应用

Molecular simulations of moveable carbon nanotube membrane for sea water desalination

设计了1个简单的移动式反渗透膜盐水分离体系,其中,移动式反渗透膜由扶手椅型(6,6)纳米碳管簇及石墨烯封装膜组成,盐水的密度为1.04g·cm-3,为近似的海水盐浓度.该设计利用纳米碳管膜的通水阻盐特性,通过外力推动膜运动实现盐水的反渗透分离.为检验其可行性与盐水分离效率,利用非平衡分子动力学模拟方法,分别考察了外部推力,体系温度,膜的厚度等对体系盐水分离效率的影响.研究结果表明:(6,6)碳管簇膜可以实现盐水分离的目的,且能耗远低于现有的海水淡化技术;此外,盐水的分离效率与外部推力,体系温度以及膜的厚度紧密相关.

In this paper,a reverse osmosis filtration system is devised for water desalination.The system consists of a box of salt and water with an approximation density of sea water（1.04g·cm-3）,a moveable carbon nanotube membrane,in which a bunch of single-walled carbon nanotubes（SWNT）is encapsulated by two pieces of graphene.On base of water translocation and salt rejection for（6,6）carbon nanotube,when moving the carbon nanotube membrane by external force,the system can be used for desalination.In order to investigate the feasibility and efficiency of the system,nonequilibrium molecular simulations were carried out.The effects of the external pushing force on the membrane,the temperature as well as the width of membrane on the efficiency of desalination are discussed.The results showed that：the membrane formed by a bunch of armchair（6,6）single-walled carbon nanotubes has the property of water transportation and salt rejection,and the energy consumption is much lower than the existing desalination technology.In addition,the efficiency of water desalination is closely dependent on the external force and temperature of the system and width of the membrane.