The preferential permeation of ions across carbon and boron nitride nanotubes

The preferential permeation of Ca2+ and Cl- ions across (7,7) and (8,8) carbon and boron nitride nanotubes have been investigated by molecular dynamics simulation method. The simulated systems composed from a carbon, or boron nitride nanotube inserted in a silicon nitride membrane immersed in the aqueous ionic solution, in the presence of an electrical field. The water structure inside nanotubes has been analyzed and the retention time of the ions, the radial distribution functions and normalized transport rate of water with respect to the number of transported ions have been calculated. The results show that the permeation of ions across the nanotubes is dependent on the diameter of the considered nanotubes. The considered nanotubes have been fixed in a silicon-nitride membrane and an external electrical field has been applied on the systems along the axis of nanotubes. (C) 2012 Elsevier Inc. All rights reserved.