Most water in the world is as saline water in seas and oceans. Desalination technology is a promising method to solve the global water crisis. Recently, many attentions have been paid to the graphene-based membranes in water desalination due to their low production cost and high efficiency. In this paper, molecular dynamics simulations are employed to investigate the effect of functionalized graphene nanosheet (GNS) membranes on the performance of salt separation from seawater in terms of water permeability and salt rejection. For this purpose, the hydrogenated (–H) and fluorinated (–F) pores were created on the GNS membrane. Then, the functionalized graphene membrane was placed in the middle of the simulation box in an aqueous ionic solution containing Na+ and Cl? ions. The applied pressure (in the range of 10–100 MPa) was used as the driving force for transport of water molecules across the reverse osmosis (RO) graphene-based membrane in order to obtain the water permeability and salt rejection. Also, radial distribution functions (RDFs) of ion–water and water–water as well as the water density map around the membrane were obtained. The results indicated that the hydrophilic chemical functions such as fluorine (–F) can improve the water permeability at low pressures.
相似文献Desalination of seawater can be an effective way to access drinking water. In this study, the performance of functionalized silicon carbide nanosheet (SiCNS) membranes for water desalination was investigated using molecular dynamics (MD) simulations. For this purpose, four types of membranes with various functionalized pores were considered to investigate their capabilities in water desalination. The chemical functions of fluorine (–F) (system S1), hydrogen (–H) (systems S2 and S3), and hydrogen (–H) and hydroxyl (–OH) (system S4) were bonded to the pore edge of the SiCNS membranes. Also, the effect of the number of pores in the membrane on the water permeability was studied between systems S2 and S3. The SiCNS membrane was placed at the center of the simulation box and the external pressure was applied to the system in the range of 10–100 MPa. The water permeability, salt rejection, potential of mean force of ions, water density, water density map, and radial distribution function (RDF) of water molecules were calculated in this work. The results demonstrated that the water permeability increases by adding hydrophilic chemical functions such as –F and –OH on the pore edge.
相似文献