Preparation Of Graphene Oxide-based Composite Membrane And Study On Oil-water Separation Performance

The global water pollution problem has become more and more serious along with the rapid development of social economy and industry.The wanton discharge of oily wastewater has caused serious harm to human survival and ecology.Membrane separation technology is widely used in the treatment of oily wastewater due to its low energy consumption,simple operation and no secondary pollution.As an emerging separation membrane material,graphene oxide(GO)has attracted people's attention because of its advantages such as good hydrophilicity,good flexibility,and good dispersibility in water.In view of the problems of poor separation performance and easy contamination of the current oil-water separation membrane materials,this paper adopts the modified Hummers method to prepare graphene oxide dispersion,and the graphene oxide self-supporting membrane and the vacuum swelling filtration method were used to prepare the graphene oxide self-supporting membrane and Graphene oxide film,doped with halloysite nanotubes and graphene oxide nanosheets,and prepared graphene oxide/Halloysite nanotube(GO/HNTs)composite membrane by vacuum filtration method,The composition,structure,wettability,oil-water separation performance,chemical stability,and recyclability of composite membrane materials were studied to provide technical support for the development of high-performance oil-water separation membrane materials.The following main conclusions were obtained:(1)The graphene oxide self-supporting membrane prepared by toluene swelling paraffin method has good flexibility,but its separation effect on toluene emulsion is poor.The graphene oxide membrane prepared by vacuum suction filtration has good hydrophilic properties(WCA=41 °),oleophobic properties(OCA>142 °),and good separation performance for toluene emulsion.When the amount of graphene oxide is used When it is 6ml,the separation water flux can reach 480 Lm-2h-1,and the separation eff-iciency can reach 99.9%.(2)FTIR,XPS and EDS analysis showed that halloysite nanotubes and graphene oxide were doped together,and a GO/HNTs composite membrane was successfully prepared.SEM and TEM analysis showed that the surface of the GO/HNTs composite film was convex and halloysite nanotubes were interposed between the graphene oxide films,and the interlayer spacing of the graphene oxide films increased.(3)Compared with graphene oxide,GO/HNTs composite membranes have better hydrophilic properties(WCA=10 °)and superoleophobic properties(OCA>150 °).GO/HNTs composite membranes have excellent separation performance for toluene,cyclohexane,dichloroethane,and soybean oil.The separation flux for toluene emulsion reaches 1470 Lm-2h-1,and the separation eff-iciency reaches 99.5%.(4)After immersed in strong acid and strong alkali solution for 12 hours,it still maintains good oil-water separation performance,and the separation water flux can reach more than 1400Lm-2h-1,showing good chemical stability.(5)The anti-fouling performance of the GO/HNTs composite membrane is excellent,and it still has a good separation flux after 10 cycles,which is 70%of the first water flux,which can be recycled.