受限于纳米碳管中盐溶液的分子动力学模拟  

A dynamic molecular simulation of a salt solution confined in carbon nanotubes

作　　者：李燕[1] 贾玉香[1] 胡仰栋[1] 

机构地区：[1]中国海洋大学化学化工学院,山东青岛266100

出　　处：《哈尔滨工程大学学报》2011年第2期242-245,共4页Journal of Harbin Engineering University

基　　金：国家自然科学基金资助项目(20806076);国家重点基础研究发展计划"973"基金资助项目(2003CB615706)

摘　　要：以纳米碳管构筑新型渗透膜实现水脱盐,为了研究对盐、水在管中的受限行为,采用分子动力学模拟,在300K、1.01×105 Pa下,以(6,6)、(8,8)2种扶手椅型纳米碳管构筑膜通道,考察了水和钠离子在2种不同直径碳管中的扩散行为.通过模拟和分析得到了受限体中水和离子的平衡构型,水分子的轴向密度分布以及钠离子在水相及管内的水合数.模拟结果表明,水分子可以快速通过(6,6)、(8,8)2种直径的碳管,而钠离子只能通过(8,8)型直径较大的碳管,即钠离子在盐溶液中以水合离子的形式存在,离子的有效直径较大,因此可以认为纳米碳管具有通水阻盐的特性,即借助相关管径的纳米碳管可以实现盐与水的分离.A comprehensive understanding of the confined behavior of salt and water in carbon nanotubes was required for the construction of novel membranes for the separation between salt and water.Dynamic molecular simulations were performed at 300K and 1.01×105 Pa to study the behavior of water molecules and ions in（6,6） and（8,8） armchair-type carbon nanotubes which were hexagonally packed to form the membranes of water and ions.Simulation results were analyzed,and the equilibration configurations of water and ions in two types of carbon nanotubes were obtained,as well as the axial density profile of water in and out of carbon nanotubes,and coordination numbers of Na＋ in carbon nanotubes and bulk solutions.The results show that water molecules can enter（6,6） and（8,8） carbon nanotubes rapidly,but Na＋ can only enter（8,8） tubes when there is hydration of Na＋ by water molecules which results in the larger effective ionic sizes.Therefore,the carbon nanotubes are thought to have the property of salt rejection and water transportation,and some carbon nanotubes can achieve the goal of separation between salt and water.

关 键 词：膜分离 纳米碳管 分子动力学 计算机模拟 盐溶液 

分 类 号：O64[理学—物理化学]