PVDF Nanofiber Membrane Preparation And Oil-water Separation Performance

The oil spills at sea and the discharge of oily wastewater from industry have caused great impact on the environment.Traditional methods have the disadvantages of low separation efficiency,high energy consumption,complicated operation process and secondary pollution.Membrane separation technology could be applied to the field of oil and water treatment due to its advantages of low energy consumption,high single-stage separation efficiency,environment friendly,etc.In this paper,polyvinylidene fluoride?PVDF?was used as film-forming material and graphene?GE?was used as dopant to prepare nanofiber membranes with the function of oil-water separation.The influence of GE on the structure and properties of nanofiber membranes was analyzed and discussed.The reinforced tubular PVDF/GE nanofiber membrane was prepared by electrospinning with polyester braided tube as support,GE as dopant,DMAc and acetone as mixed solvent.The effect of GE content on the structure and properties of the reinforced tubular PVDF/GE nanofiber membrane was studied.The results showed that the membrane has excellent mechanical properties when the fiber braided tube was used to reinforce the membrane.When the content of GE was 0.1 wt%,the water contact angle reached 147°,the pure water osmotic pressure was 75 KPa,and the membrane showed outstanding hydrophobicity and oil-water separation characteristicsPolyvinylidene fluoride microspheres/?polyvinylidene fluoride/graphene?nanofiber composite membrane was prepared by electrostaticspray deposition with reinforced tubular PVDF/GE nanofiber membrane as receivers and PVDF as polymer.The effect of PVDF content on the morphology of microspheres was analyzed,the structure and properties of the PVDF_ms/?PVDF/GE?nanofiber composite membrane was discussed.The results showed that the microsphere-fiber composite structure could effectively control the pore size and distribution of the nanofiber composite membrane.When the content of PVDF was 10 wt%,the microsphere-fiber composite structure was obvious,which endowed PVDF_ms/?PVDF/GE?nanofiber composite membrane with excellent demulsification performance,and the separation efficiency for kerosene/water emulsion reached 99.85%.?Polyvinylidene fluoride/graphene?microspheres/?polyvinylidene fluoride/graphene?nanofiber composite membrane with loose microsphere-fiber composite structure was prepared by electrostaticspray deposition using reinforced tubular PVDF/GE nanofiber membrane as receivers,GE as dopant and PVDF as polymer.The results showed that when the content of GE was 0.05 wt%,the loose microspheres-fibers composite structure was better,which endowed the?PVDF/GE?_ms/?PVDF/GE?nanofiber composite membrane with superhydrophobic characteristics?152°?and excellent demulsification performance.The separation efficiency of kerosene/water emulsion reached 99.53%and the separation flux was3110 L·m^-2·h^-1.10 cycles later,?PVDF/GE?_ms/?PVDF/GE?nanofiber composite membrane still maintained excellent separation performance.