Selectively Enhanced Ion Transport In Graphene Oxide Membrane/PET Conical Nanopore System

Graphene oxide(GO)as an emerging 2D material has attracted a lot of research interests due to its high specific ratio,oxygen-containing groups on the surface and great mechanical property.And it has been used in gas and ion separation,nanocomposites and energy conversion area.The functional membranes based on graphene oxide have abundant nanochannels which can selectively separate ions by the size and charge of ions.And the water flux of graphene oxide membrane is extremely high which can be the separation membrane for desalination and ion separation in the next generation.Firstly,the single PET conical nanopore was obtained by combining heavy ion irradiation with chemical etching.After that,the graphene oxide membrane(GOM)was formed on the single PET conical nanopore by spin-coating to get the GOM/PET system.The ion transport in graphene oxide membrane was investigated by comparing these two structures.Comparing to pure single PET conical nanopore,the existence of GOM made the ion rectification ratio increase from 4.5 to 238.0 in KCl solution.Then the same measurements in other solutions were carried out to verify the universality of this method.Besides these,the cation selectivity and the pH stability of the GOM/PET were both studied.The results indicated that the graphene oxide can greatly enhance the cation selectivity of single PET conical nanopore and keep the direction of rectification effect unchanged.Finally,simulation was exploited to explain the origin and enhancement of rectification effect in GOM/PET system.