| In recent years,the discharge of oil spill and oily sewage has caused serious damage to the ecological environment.It is particularly important and urgent to develop a method with high efficiency of oil and water purification.At present,oil skimmer,centrifugation,membrane separation and other technologies have made great achievements in the separation of oily wastewater.However,oil skimmer,centrifugation and other technologies have some problems,such as low separation efficiency,high energy consumption and secondary pollution.In the membrane separation technology,electrostatic spinning method not only has the characteristics of simple equipment,controllable process,wide spinning range and low cost,but also the nanofiber membrane prepared has the advantages of good fiber uniformity and high porosity.The huge technological and finished product advantages make it have broad application prospects in the fields of biomedicine,clothing,filtration materials and so on.However,although the nanofibers prepared by electrostatic spinning have made some progress in the field of oil-water separation,the existing membrane materials still have the problem of low separation efficiency.At present,most nano-fiber membranes use mixed spinning to attach inorganic nanoparticles to the surface of the fiber membrane,so as to increase the surface roughness.The nano inorganic particles attached to the surface of the nanofiber membrane prepared by this method have poor bonding with the fiber membrane,and the surface particles are easy to fall off after a certain period of use,and the selective wettability of oil and water can be greatly reduced.At the same time,the damage of nanofiber membrane structure affects its long-term recycling performance.Therefore,it is a key problem to develop a kind of oil-water separation membrane which can purify oil and water efficiently and meet the requirements of long-term use.In this paper,a kind of oleophilic/hydrophobic oil-water separation membrane was prepared using polylactic acid（PLA）,fluorinated polyurethane（FPU）and hydrophobic vapor phase Si O2 as raw materials by electrostatic spinning technology.The contact Angle of the prepared nanofiber membrane reached 140.4°in air,149.6°in oil-water,and 0°in oil.In terms of oil-water separation performance,the oil separation flux of diesel/water emulsion without surfactant reached 237.4 L m-2 h-1,and the water content of filtrate was 54ppm,The Span80/diesel/water emulsion oil separation flux reached 346.8 L m-2 h-1 and the water content in the filtrate was 84.8ppm.At the same time,after 10 cycles of oil-water separation tests PLA nanofiber membrane still showed excellent oil-water separation performance,meeting the requirements of long-term recycling.The excellent oil-water separation performance of PLA nanofiber membrane makes it have a broad application market in the field of oily sewage treatment.Then,using polyvenethylidene fluoride（PVDF）and fluorinated polyurethane（FPU）as raw materials,according to the hydrophobic principle of lotus leaf surface,we prepared a lotus leaf effect oil-water separation composite membrane by combining electrostatic spinning/electrostatic spraying technology.The prepared separation membrane has excellent oil and hydrophobic properties in air and superhydrophobic properties under oil.The contact Angle of water in air is 150.2°,the contact Angle of oil-water is 159.1°,the separation flux of diesel/water emulsion oil without surfactant is 116.3 L m-2 h-1,and the water content of filtrate is 43.6ppm.The Span80/diesel/water emulsion oil separation flux for surfactant stabilization reached 253 L m-2 h-1,and the water content in the filtrate was 58.1ppm.In addition,after 10cycles of use the lotus leaf effect separation membrane still maintains excellent oil-water separation effect,to meet the needs of long-term recycling.The excellent oil-water separation performance and recycling performance make the lotus leaf effect separation membrane show great application prospect in oily wastewater treatment and other fields. |
