Study On Preparation And Properties Of Modified Graphene Oxide Composite Nanofiltration Membrane

The oxygen-containing functional groups on the surface of Graphene oxide(GO)makes it good dispersibility,hydrophilicity and compatibility with polymer,and they also provide a large number of active sites for further modification.Carboxylated graphene oxide(CFGO)has better water solubility and compatibility with polymers due to the deprotonation of a large number of carboxyl groups on the surface.In this paper,using polysulfone membrane as support membrane,piperazine and trimesoyl chloride as monomer,the GO/ CFGO as additives in water,polyamide nanofiltration membranes were prepared by interfacial polymerization(IP).On this basis,the composite membranes were characterized by the permeability,and its application in dye desalination of dyes and antifouling was also investigated.First,Graphene oxide(GO)was prepared by the Hummers' method,then treated by hydrobromic acid and oxalic acid to prepare CFGO.The chemical structure and morphology of two products were characterized by Reflectance-Fourier transform Infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS),and the hydrophilicity was characterized by contact angle goniometer,and their dispersing property was studied using UV/vis and Zeta potential analysing.Then,the GO/ CFGO composite nanofiltration membrane was prepared by adding different amounts of GO/ CFGO into aqueous solution.The surface morphology of the membranes was characterized by scanning electron microscopy(SEM)and atomic force microscopy(AFM),the chemical structure of the membranes was characterized by Fourier infrared spectroscopy(FTIR)and X ray photoelectron spectroscopy(XPS).The surface hydrophilicity of the membranes was measured by contact angle and the surface potential was measured by Zeta potential analyzer.Results show that the CFGO has better dispersion performance in the membrane,and makes the composite membrane have better hydrophilicity.In the experiment of membrane permeability,the pure water flux of the composite nanofiltration membrane was increased with the increasing of the concentration of GO/ CFGO.When the concentration of GO was 0.05%,and the concentration of CFGO was 0.07%,the pure water flux of GO/PA membrane and CFGO/PA membrane reached the maximum value,and then began to decline.The application of the composite membrane in the desalination of the dye was also studied.When the addition amount of the CFGO was 0.07%,the flux of the composite membrane reached 110.4 L*m-2*h-1,which is close to the pure water flux.Results showed that the application prospect of CFGO/PA membrane in the desalination and concentration of dyes is huge.Finally,the antifouling performance of the composite membrane was investigated.The addition of CFGO reduces the surface roughness of the membrane and makes the membane surface with more negative charges.Therefore,the antifouling performance of the composite membrane modified by CFGO is better.