| Oily wastewater has caused serious environmental pollution and huge economic loss,and oil/water separation has become a research hotspot in recent years.Now,membrane separation technology has been widely used in oil/water separation process due to its advantages of high efficiency,easy operation and no secondary pollut ion.Along with the properties such as high porosity and large specific surface area,the electrospinning nanofiber membrane has a broad application in the field of oil/water separation and catalytic degradation.However,in practical application,the surface of electrospinning oil/water separation membrane is easy to be wetted by water.Moreover,the function of the target membrane is commonly simple,which hindered its further practical application.In this paper,three-dimensional tubular polyvinyl chloride(PVC)nanofiber membrane was prepared by electrospinning method based on the design of three-dimensional membrane structure,and its structure and performance were optimized.,The three-dimensional tubular PVC/silicon dioxide(SiO2)nanofiber membrane was prepared by synchronous electrospraying and electrospinning process,with the poly(ethylene terephthalate)(PET)braided tube as the support and hydrophobic nano SiO2 as the inorganic additive.The fabrication strategy was designed as the double-needle electrospinning methods with two-component in respective needles.The effect of the introduction of hydrophobic nano SiO2 on the continuous three-dimensional membrane structure was studied,and the structure and performance of the membrane were optimized by regulating the content of hydrophobic nano SiO 2.The results indicated that the synergistic effect of two-dimensional nanofibers interwoven with three-dimensional microspheres endowed the three-dimensional nanofiber membrane with the continuous water-oil-solid interfaces during oil/water separation process,which slowed down the water wetting process and improved the hydrophobic stability of the membrane.Owing to the high porosity and multistage rough structures,as-prepared three-dimensional nanofiber membrane can efficiently separate a sesies of surfactant-stabilized water-in-oil emulsions without using external force.When the SiO2 content reached up to 4 wt%,the membrane possessed excellent lipophilicity and under oil superhydrophobicity.Moreover,its permeation flux can reach up to 358.60 L/m2.h with outstanding separation efficiency more than 95%under the driving of gravity.In addition,the excellent reusability was also presented during 10 cycles of water-in-oil emulsion separation.The three-dimensional tubular PVC/SiO2/SiO2@Ag nanofiber membrane was prepared by electrospinning,with the three-dimensional tubular PVC/SiO2 nanofiber membrane as matrix and functionalized SiO2@Ag nanoparticles as inorganic additives.The effect of the content of SiO2@Ag functional nanoparticles on the structure and properties of the membrane was studied,and the synchronous oil/water separation and dye degradation properties were also investigated.The results showed that the three-dimensional hydrophobic structure of the tubular PVC/SiO 2 nanofiber membrane endowed the membrane with excellent hydrophobic stability,which could achieve good oil/water separation performance.The SiO2@Ag nanoparticles endowed the membrane with excellent catalytic degradation properties.The synergistic effect of the three-dimensional hydrophobic structure of the tubular PVC/SiO 2 nanofiber membrane and the SiO2@Ag ultra-thin catalytic layer enabled as-prepared membrane to have the properties of synchronous oil/water separation and catalytic degradation.When the SiO2@Ag content reached up to 6 wt%,the membrane possessed high oil removal rate(96%)and methylene blue(MB)removal rate(95%)in the oil/water separation and catalytic degradation process.In addition,the SiO2@Ag nanoparticles on as-prepared nanofiber membrane had good binding properties with PVC nanofibers,and the membrane showed excel ent reuse performance. |
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