海藻酸钠基多级结构纳米纤维膜的制备与性能研究

【作者】 杨锦铸；

【导师】 袁华；

【作者基本信息】 青岛大学 ， 材料学， 2023， 硕士

【摘要】 如今社会上污染情况日益加剧,地球上的水资源和大气都遭到了严重破坏,现在已经变成了制约社会发展和科技进步的重大因素,所以,处理空气污染和水污染问题迫在眉睫。传统的膜分离材料在空气过滤及水油分离等方面发挥着重要作用,但仍存在着过滤精度低、难以实现高效低阻等问题。静电纺纳米纤维材料具有纤维直径小、比表面积大、孔径小、孔隙率高及纤维膜内部孔洞联通性好等优点,在空气处理及水处理等多种应用场景发挥重要作用。海藻酸钠（SA）作为一种来源于海藻的天然生物材料,具有生物相容性、可生物降解性、可加工性和低成本等特性,在实验室和工业中受到了广泛的关注。本课题中,利用静电纺丝技术,通过调控溶质浓度和溶剂配比等实验参数对纳米纤维形貌的影响,利用流变、SEM等表征技术,得出最佳的静电纺丝工艺参数,制备了具有串珠状结构的SA纳米纤维膜,探索了其在空气过滤等方面的应用。致密的SA纤维膜的过滤效率在99%以上,但是阻力压降高达330 Pa。而具有串珠状的SA纤维膜的过滤效率随着气溶胶粒子直径的降低,过滤效率有所下降,但是串珠状纤维膜的阻力压降也随之降低较明显,纺丝液的浓度为2.6%制备的纤维膜的阻力压降约100 Pa,品质因子为0.0284 Pa^-1,此时其气体过滤效果最为理想。基于静电纺丝和静电喷雾技术的表面润湿性改性方法,在SA纳米纤维膜的基础上,通过静电喷雾技术涂覆了一层Zn O/SA功能薄层,制备出了具有的超亲水-水下超疏油性能的微球层/纳米纤维复合膜;探索了Zn O/SA浓度对微球层形貌结构的影响规律;分析了微球层对复合纤维膜表面的孔径、表面粗糙度、选择润湿性的影响。研究结果表明高亲水性的聚合物本体和多级的粗糙结构在膜表面形成稳定水化层,减少了油滴与膜本体的接触面积,表现出优异的防污染性能。含油污水的实验证明,复合纤维膜不仅可以分离油水混合物,还可以用于油水乳浊液的分离,分离的流通量高达800 L·m^-2·h^-1,并表现出良好的循环性能。另外,Zn O的加入提高了复合纤维膜的抗菌效果,得到具有多功能特性的可应用于水处理等领域的纤维膜。更多还原

【Abstract】 Nowadays,the pollution situation in society is becoming increasingly severe,and the water resources and atmosphere on Earth have been severely damaged.It has become a major factor restricting social development and technological progress.Therefore,it is urgent to address the issues of air and water pollution.Traditional membrane separation materials play an important role in air filtration and water oil separation,but there are still problems such as low filtration accuracy and difficulty in achieving high efficiency and low resistance.Electrospun nanofiber materials have the advantages of small fiber diameter,large specific surface area,small pore size,high porosity,and good connectivity of internal pores in fiber membranes,playing an important role in various application scenarios such as air and water treatment.Sodium alginate（SA）,as a natural biomaterial derived from algae,has been widely concerned in laboratory and industrial applications due to its biocompatibility,biodegradability,processability and low cost.In this study,electrospinning technology was used to investigate the effects of experimental parameters such as solute concentration and solvent ratio on the morphology of nanofibers.The optimal electrospinning process parameters were obtained by combining rheological and SEM characterization techniques.SA nanofiber membranes with bead like structures were prepared,and their applications in air filtration were explored.The filtration efficiency of the dense SA nanofiber membrane is over 99%,but the resistance pressure drop can reach up to 330 Pa.The filtration efficiency of the beaded SA nanofiber membrane decreases with the decrease of the aerosol particles,but the resistance pressure drop of the beaded nanofiber membrane also decreases significantly.The resistance pressure drop of the nanofiber membrane prepared with the concentration of the spinning solution of 2.6%is about 100 Pa,and the quality factor is 0.0284 Pa^-1.At this time,its gas filtration effect is the most ideal.Based on the surface wettability modification method of electrostatic spinning and electrospraying,on the basis of SA nanofiber membrane,a layer of Zn O/SA functional thin layer was coated by electrospraying technology,and a micro sphere layer/nanofiber composite membrane with super hydrophilic underwater super oil repellent performance was prepared.Explored the influence of Zn O/SA concentration on the morphology and structure of the microsphere layer.The effects of Zn O particles on the pore size,surface roughness,and selected wettability of composite fiber membranes were analyzed.The highly hydrophilic polymer body,high porosity skin,and rough structure form a stable hydration layer on the membrane surface,effectively reducing the contact area between oil droplets and the membrane body,and demonstrating excellent anti-pollution performance.The experiment of oily sewage proves that the composite membrane could not only separate oil-water mixture,but also been used for the separation of oil-water emulsion.The flow rate of separation is up to 800 L·m^-2·h^-1,and it shows good circulation performance.In addition,the addition of Zn O improves the antibacterial effect of composite nanofiber membranes,resulting in multifunctional nanofiber membranes.更多还原