Molecular Dynamics Simulating the Performance of Carbon Nanotubes in Water Desalination

Abstract

Recently, the use of carbon nanotubes in water treatment membranes has been proposed. Understanding the mechanism of the process in nanotubes may have a significant impact on the development of this technology. In this study, to clarify the molecular mechanism and measure the impact of the effective factors, the water desalination process by filters consisting of carbon nanotubes has been investigated by the molecular dynamics simulation method. The effect of factors such as nanotube diameter applied pressure and porosity on the process is studied. The results showed that reducing the filtration pressure increases salt rejection. However, reducing the pressure reduces the water flow through the nanotubes, which should be considered in the optimal design of the treatment system. Increasing the porosity of the membrane for a given nanotube does not have a significant effect on the desalination rate, but it greatly increases the flow rate. The simulation results showed that if the geometry studied in this study is used as a filter for nanotubes (10, 10), the flow rate of water at a pressure of 100 MPa will be equal to 7 mL/s per unit cross-section of the filter.

Keywords

• carbon nanotubes
• desalination
• molecular simulation
• porosity
• water purification