A study on the applying hydrostatic pressure process in molecular dynamics simulation for water desalination

[In this research, hydrogenated nanoporous graphene membrane NPG with reverse osmosis desalination process as a useful process was used in molecular dynamics MD simulations to estimate the region of applying hydrostatic pressure in the MD simulation cell. The NPG membrane was positioned in the middle of the box and the simulation box consists of a NPG, water, and Cl- and Na ions. The region of applying force was found by evaluation of permeability coefficient, salt rejection and pressure analysis of systems. In this study, the obtained results of MD simulation by applying pressure by piston were compared with experimental data in the same condition. The results demonstrated that the region of applying force is not an arbitrary quantity and appropriate region of applying force was in the range of 5-15 of the simulation cells. The importance of the accurate choice of the region of applying force as well as unifying this region in molecular dynamics simulations of membrane processes makes it possible to compare MD simulation results.