增强型聚丙烯腈中空纤维膜结构设计与性能研究

发布时间：2018-04-10 00:33

本文选题：聚丙烯腈　切入点：编织管　出处：《天津工业大学》2016年博士论文

【摘要】：本文以二维编织技术制备中空管状纤维织物(编织管)作为增强体,聚丙烯腈(PAN)为聚合物表面分离层,用溶液相转化法在编织管表面复合PAN表面分离层,制备同质编织管增强型PAN中空纤维膜,研究聚合物浓度、添加剂、纺丝工艺条件等对膜结构及性能影响；采用编织管增强法分别制备了异质增强型PVDF/PAN(编织管)及PAN/PET(编织管)中空纤维膜,并对增强型中空纤维膜界面结合性能进行了研究；分别以具有优良亲水性能的醋酸纤维素(CA)与PAN共混,以氧化石墨烯(GO)为添加剂掺杂改性表面分离层,研究了表面分离层改性后的增强型PAN中空纤维膜结构和性能；将同质增强膜用于膜生物反应器(MBR),研究其在MBR试验过程中的应用可行性及膜抗污染性能。利用同质材料间良好的热力学相容性、共溶剂性,以PAN中空编织管为增强体,PAN为聚合物表面分离层,制备了同质编织管增强型PAN中空纤维膜。研究发现,铸膜液中溶剂对编织管的纤维表面产生溶胀、溶解作用,使得增强膜具有良好的界面结合性能,所得增强型PAN中空纤维膜断裂强度大于75MPa,当聚合物浓度为10-12wt.%,PVP含量8 wt.%时,同质编织管增强型PAN中空纤维膜结构和性能较优。以聚酯纤维(PET)长丝编织管为增强体,PAN为聚合物表面分离层,制备异质增强型PAN/PET(编织管)中空纤维膜；以PAN编织管为增强体,PVDF为聚合物表面分离层,制备共溶剂(表面分离层与增强体之间)异质增强型PVDF/PAN(编织管)中空纤维膜。研究表明,增强膜中表面分离层与增强体之间界面结合性能主要取决于二者的热力学相容性,同质编织管增强型PAN界面结合性能最优,共溶剂异质增强型PVDF/PAN(编织管)次之,异质增强PAN/PET(编织管)型最差,共溶剂可提高异质增强型中空纤维膜界面结合性能。以PAN编织管为增强体,将亲水性聚合物CA与PAN共混作为分离层,制得增强型PAN/CA共混中空纤维膜。研究发现,增强型PAN/CA共混中空纤维膜内存在大量界面微孔：随着共混体系内CA组分含量增加,膜表面分离层内PAN由连续相逐渐过渡为分散相,而CA由分散相转变为连续相。当PAN为连续相时,增强体与膜表面分离层间界面结合牢固,类似于同质编织管增强型；而CA为连续相时,所形成界面结合较弱,类似于异质增强型。用改良Hummers法制备GO掺杂改性PAN(表面分离层),制得同质编织管增强型PAN/GO中空纤维膜。研究表明,GO分布于增强膜表面及内部膜孔壁。随着GO含量的增加,膜孔径分布变窄,膜表面粗糙度增大,亲水性显著提高：膜纯水通量和蛋白截留率增加,抗污染性增强。将同质编织管增强型PAN、PAN/GO中空纤维膜用于MBR,处理模拟城市生活污水试验。结果表明,MBR系统内对有机物的降解去除以生化作用为主,两种同质增强型中空纤维膜均可有效强化系统出水水质并提高出水稳定性,COD去除率均在97%以上：两种同质编织管增强型中空纤维膜的污染机理相似,掺杂GO改性同质编织管增强型PAN/GO中空纤维膜的抗污性更强,膜污染速率更慢,清洗频率低,运行周期更长。
[Abstract]:The preparation technology of hollow tubular woven fabric (woven pipe) as reinforcement, polyacrylonitrile (PAN) polymer surface layer, the surface of PAN composite tube surface separation layer in woven with the solution phase inversion method, the preparation of homogeneous woven tube reinforced PAN hollow fiber membrane, polymer concentration, additive research, influence the spinning process conditions on membrane structure and performance; the woven tube reinforced method were used to prepare the heterogeneous enhanced PVDF/PAN (woven tube) and PAN/PET (tube) hollow fiber membrane, and the enhanced hollow fiber membrane interfacial properties were studied respectively; cellulose acetate with excellent hydrophilic properties (CA) blended with PAN, graphene oxide (GO) modified surface layer separation as additive doping, surface modification of separation layer enhanced the structure and properties of PAN hollow fiber membrane after; membrane bioreactor will enhance the homogeneity for Reactor (MBR), studies the feasibility of MBR application in the test process and membrane pollution resistance performance. By using homogeneous materials with good thermodynamic compatibility, co solvent, PAN hollow braided tube reinforced PAN polymer surface layer separation, preparation of homogeneous woven tube reinforced PAN hollow fiber membrane. The study found that the solvent in the casting solution on the fiber surface swelling, braided tube dissolution, the enhanced membrane has excellent interfacial properties, the fracture type reinforced PAN hollow fiber membrane strength greater than 75MPa, when the polymer concentration is 10-12wt.%, the content of PVP 8 wt.%, homogeneous braided tube reinforcement structure and properties of PAN the hollow fiber membrane is better. The polyester fiber (PET) filament woven pipe reinforced PAN polymer surface layer separation, preparation of heterogeneous enhanced PAN/PET (tube) hollow fiber membrane; PAN woven tube as a strengthening body, PVDF as polymer sheet Surface separation, preparation of co solvent (surface separation layer and the reinforcement between heterogeneous) enhanced PVDF/PAN (tube) hollow fiber membrane. The results show that surface enhanced membrane separation layer and enhance the interfacial bonding between thermodynamics performance mainly depends on the compatibility of the two, homogeneous woven pipe enhanced PAN interface optimal performance of co solvent heterogeneous enhanced PVDF/PAN (braided tube) of heterogeneous enhanced PAN/PET (tube) type is the worst, co solvent can improve the bonding performance of heterogeneous hollow fiber membrane interface is enhanced. With PAN braided tube as reinforcement, the hydrophilic polymer CA was blended with PAN as separation layer was enhanced type PAN/CA blend hollow fiber membrane. The study found that the enhanced PAN/CA blend hollow fiber membrane in the existence of a large number of micro interface: with the CA content in the blends increased, membrane separation layer PAN by continuous phase transition as the dispersed phase, and C A consists of dispersed phase to continuous phase. When the PAN is in continuous phase, combined with solid body and membrane surface separation interface enhancement, similar to the homogeneous braided tube enhanced; while CA is in continuous phase, the formation of interfacial bonding is weak, similar to the heterogeneous enhanced. With the modified Hummers prepared by GO doping PAN (surface layer), prepared homogeneous braided tube reinforced PAN/GO hollow fiber membrane. The study shows that the distribution of GO in reinforced membrane surface and internal pore walls. With the increase of GO content, membrane pore size distribution becomes narrow, the surface roughness increases, the hydrophilic membrane significantly improved: the pure water flux and protein retention the rate of increase in anti pollution increased. The homogeneous braided tube reinforced PAN, PAN/GO hollow fiber membrane for treatment of city sewage MBR, simulation test. The results show that the MBR system in the degradation of organic matter removal by biochemical effect, two kinds of homogeneous enhancement type hollow fiber membrane Can effectively enhance the quality of effluent water and improve water stability, the removal rate of COD were above 97%: two different braided tube reinforced hollow fiber membrane fouling mechanism similar to that of GO doped modified homogeneous woven tube reinforced anti pollution more type of PAN/GO hollow fiber membrane, the membrane fouling rate is slower, the cleaning frequency is low, a longer operation cycle.

【学位授予单位】：天津工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TQ028.8

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