Water Treatment with Cation Selective Porous Graphene and Boron Nitride Membrane: A Molecular Dynamics Investigation

Abstract

Almost any societies facing with achieving and developing the most efficient method of water treatment. The nanotechnology innovative achievement, provided a variety of nonporous membrane for water treatment application. High permeability of water and high rejection of salt are essential properties of these membranes and have been investigated as an efficient way for water desalination. All of these systems have been designed in a way that ions do not pass and water molecules permeate through the nanopores, so clean water is obtained through this process. But, in this research, we employed permeation of heavy metallic ions through the passivated nanopores under electric field to purify water from such contaminations. We employed molecular dynamics calculations to investigate the removal of heavy metallic ions from water using 2D boron nitride and graphene membrane. A nanopore of 6 Å diameter is located in the middle of graphene and 2D boron nitride membranes, the pores passivated by fluorine atoms which is shown to favor cations permeation. Potential mean force calculation, water density profile, number of ions permeation and required time for an ion to pass through nanopore both in graphene and 2D boron nitride membranes have been obtained and the results indicate, that 2D boron nitride has a better performance in cation permeability than graphene.