Investigation On Graphene And Its Derivatives For Desalination

With the rapid development of science and technology and the increasing population in the world,the shortage of freshwater resources and the problem of water pollution in the world are becoming more and more serious,which poses a great threat to the earth's ecological environment and human security.This has prompted people to work on various water treatment technologies.Membrane separation technology is a green,low-energy,high-efficiency treatment method that has great advantages in water treatment.In recent years,the manufacturing technology of graphene and its various derivatives has developed rapidly,and its application has become more widespread.Graphene,as the atomic-scale film with the highest hardness,has attracted wide attention.In this paper,experimental and molecular dynamics methods were used to study the transport properties of graphene and its derivatives.Firstly,the folded graphene film is prepared by self-assembly method to study the relationship between the infiltration pressure of water molecules flowing between the folded graphene film layers and the film thickness by driving water molecules through different thicknesses of folded graphene film.Secondly,the permeation model of functional group modified single-layer porous graphene film was built to study the effects of pressure,pore area and functional group modification on the cross-layer flow of water molecules and salt ions.It has been found that the water flux of water molecules in cross-layer flow is related to the modification of area and functional groups,independent of pressure;the interception of salt ions in crosslayer flow is related to pressure,pore area and modification of functional groups.The modification of the functional group to the salt ion reflects the selective permeability.Finally,the permeation model of functionally group modified double-layer porous graphene films was built to study the effects of pressure and interlayer spacing on the inlayer and cross-layer flow of water molecules and salt ions.It is found that when the interlayer spacing is small,the controlling factor affecting the permeation behavior of water molecules is interlayer flow.When the interlayer spacing is large,the controlling factor affecting the permeability of water molecules is cross-layer flow.The rejection of salt ions inlayer and cross-layer flow is related to the pressure and layer spacing.