Electrokinetics desalination of water using fluorinated carbon nanotubes embedded in silicon membrane: Insights from molecular dynamics simulation

- Interestingly, this research introduces fluorinated carbon nanotubes for transporting higher flux of water compared to pristine carbon nanotubes.
- Applying electrical field resulted in a dramatic increase in water transport through fluorinated carbon nanotubes.
- Water self-diffusion coefficient through fluorinated carbon nanotubes were more than pristine carbon nanotubes.
- This work with precise analysis of water transport through pristine and fluorinated carbon nanotubes introduce fluorinated CNTs as a promising candidate in water desalination membrane technology.

A molecular dynamics simulation was performed to investigate the transport properties of water, sodium and chlorine ions through double-end fluorinated carbon nanotubes (FCNT) under the horizontal electrical field. The present system consists of a carbon nanotube embedded in silicon membrane and two, water box placed at both sides of the membrane. The flow and structure analysis shows that FCNTs in a specific range of electrical field enhance the water flux. Furthermore, the flow significantly depends on carbon nanotubes radii. In FCNT (8,8) the water flux is increased to ∼215 H2O/ns which is 25% more than water flux in pristine carbon nanotubes. In FCNT (10,10) water flux increased to ∼600 H2O/ns which interestingly explain the improvement of water flux through fluorinated carbon nanotubes. The transport of water in FCNT and PCNT were scrutinized by other parameters such as hydrogen bonds, radial distribution function (RDF) and ionic current analysis. Results revealed the influence of fluorine functionalization on carbon nanotubes, headed for the increment of water transport through carbon nanotube based nanopore. Our results also put forward that fluorinated SWCNTs may be used as a design model in CNT-based water storage devices and water purification membranes.