【作者】 刘雷艮；

【导师】 潘志娟；

【作者基本信息】 苏州大学 ， 纺织材料与纺织品设计， 2013， 博士

【摘要】 膜分离作为一种清洁生产技术，以其优良的分离效果、操作条件温和、设备简单等优点，广泛应用于工业废水回收利用和特种水处理工业。采用膜分离技术处理染料废水可以实现染料的资源回收和清洁生产。分离膜的制备方法很多，而近年来通过静电纺丝获得的纤维膜，以其高比表面积和表面吸附能，及贯通的孔隙结构和高孔隙率，受到研究者的普遍关注。聚砜（Polysulfone，PSF）因具有优良的化学稳定性和热稳定性而广泛应用于污水处理膜材料。通过静电纺丝技术可以获得纤维直径在几百至几微米的PSF纤维膜，其孔径为数微米。PA6/66具有较好的化学稳定性，经静电纺丝获得的纤维直径可达几十纳米，纤维膜孔径可达到纳米级。这两类静电纺纤维膜在污水处理及染料废水处理方面具有潜在的应用前景。但是目前有关静电纺PSF纤维膜和PA6/66纤维膜对染料废水过滤效果的系统研究仍处于空白。本文探索与优化了PSF的静电纺丝工艺，并针对静电纺PSF纤维膜强力较低的问题，采用热处理的方法使其力学性能得到显著改善。结果表明，以DMF为溶剂，在纺丝液质量分数为20%，纺丝电压为12kV，纺丝距离为15cm，纺丝液流量为1.5ml/h的条件下制备的静电纺PSF纤维具有良好的微观形貌，并且纺丝状态稳定。采用接近PSF熔点温度对其静电纺纤维膜进行张力下干热处理，并得到最佳热处理工艺条件为：处理温度为190℃，处理时间为2h，此时膜的平均孔径为4.5μm，表面接触角为130.2°。针对染料废水高酸碱度特性及采用化学试剂清洗膜时，对材料的化学稳定性和湿热稳定性的需求，研究了常温下静电纺PSF和PA6/66纤维膜在不同pH值的盐酸和氢氧化钠溶液、去离子水、常用杀菌剂1%双氧水和0.5%次氯酸钠溶液中的稳定性，及其在去离子水中的湿热稳定性。结果表明，190℃-2h热处理后的静电纺PSF纤维膜在上述溶液中具有优异的化学稳定性，在60℃以下的去离子水中具有优良的湿热稳定性，但是在80℃热水处理4+4d后，纤维膜的外观形态和孔隙结构受到严重破坏。经90℃-15min湿热处理后的静电纺PA6/66纤维膜，在双氧水和次氯酸钠溶液中处理4d后，其力学性能遭到严重破坏，而在其他试剂中浸泡处理4+4d后，仍能保持原有的形态结构，力学性能保持性较好；在40℃热水中处理4+4d后，仍然能保持较好的力学性能，而在60℃热水中，随着处理时间增加，力学性能遭到严重破坏。为了改善静电纺PSF纤维膜的亲水性，减小膜孔径，并能进一步提高膜的断裂强度，减小断裂伸长，以达到去除染料，减少膜污染和减小过滤时由于过滤压力而引起的膜变形情况，先采用氧气等离子体预处理静电纺PSF纤维膜，再采用戊二醛交联壳聚糖溶液浸轧处理纤维膜。结果表明，经交联壳聚糖溶液浸轧处理后，纤维膜的孔径减小，力学性能和亲水性能均显著改善。经2%-120（壳聚糖质量百分数-戊二醛体积/μl）交联壳聚糖溶液处理后，纤维膜的部分孔隙被壳聚糖膜覆盖，孔径小于0.09μm，并且初始模量和断裂强度分别增加了277.2%和126.8%，断裂伸长率减小了86.9%。经2%-100交联壳聚糖溶液处理后，纤维膜平均孔径由4.5μm减小为2.62μm，初始模量和断裂强度分别增加了134.7%和53.9%，断裂伸长率减小了77.2%。研究了死端恒压过滤条件下，经190℃-2h干热处理后的静电纺PSF原样、2%-100改性PSF、2%-120改性PSF和经90℃-15min湿热处理后的PA6/66纤维膜对分散蓝2BLN悬浮液和弱酸性蓝N-RL水溶液的过滤性能。结果表明，在0.1MPa恒压过滤条件下，分散蓝2BLN悬浮液为0.1g/L时，2%-120的截留率为99.5%，但是过滤通量远小于其他三种。除此之外，其他三种纤维膜的截留率相近，均达94%以上，经25min后，这三种纤维膜的过滤通量趋于一致。当过滤压力从0.1MPa增加到0.3MPa时，2%-120改性PSF纤维膜对分散蓝2BLN的截留率并没有发生明显变化，增加压力也未能使其通量有大幅度提高。此外，研究还发现，多层叠加纤维膜没有达到提高过滤效果的目的；分散蓝2BLN悬浮液的浓度与静电纺PSF纤维膜对其截留率之间没有显著的关系。静电纺PSF原样、PA6/66及两者的复合纤维膜对0.1g/L弱酸性蓝N-RL的截留率均较小，过滤后的滤液色度没有显著变化，但稳定过滤通量与过滤分散蓝2BLN相似，均在45～51L/m2.h范围内，而2%-120改性PSF对弱酸性蓝N-RL溶液的截留率可达92.4%，过滤后滤液颜色明显变浅，具有较好的效果，但是过滤通量小仍然是该试样的主要缺陷。更多还原

【Abstract】 Membrane filtration is a clean producing technique, which has excellent separationefficiency, mild operating conditions and simple equipments, so that it is widely used inindustry waste water and special waste water treatment. It can be realized that the dyes arerecycled in dying waste water through membrane filtration. Although there are manymethods to prepare filtration membranes, the electrospun fibrous membrane is paidextensive attention for their high specific surface area, throughout pores and high porosity.Polysulfone (PSF) is widely used as waste water filtration membrane material for itsexcellent chemical and thermal stability. The diameter of PSF fibers can reach fromhundreds to thousands nanometer through electrospinning technique, and the pore size ofelectrospun PSF membrane can reach thousands nanometer. Meanwhile PA6/66also hasgood chemical stability, and its electrospun fiber diameter can reach dozens of nanometer,its membrane pore size is to a few nanometers. So these two electrospun membranes havepotential application in dye waste water. But till now, there was not systematic research ofthese two membranes used in filtering dye waste water.In this paper，the parameters of electrospun polysulfone fibrous membrane wereoptimized. In order to improve the strength of the membrane which was obtained atoptimized parameters, dry heat treatment parameters were also optimized. The resultsshowed that when polysulfone was dissolved in DMF under room temperature, theconcentration of spinning solution was20wt%, spinning voltage was12kV，collectingspinning distance was15cm，solution flow rate was1.5ml/h, the obtained fibers had bettermicro-morphology. When the optimized membrane was treated at190℃for2h withloading tension, the membrane has better mechanical property, which can be regarded asthe optimized heat treating parameters. The average pore size of membrane was4.5μm andits surface contact angle was130.2°under this condition.The pH value of dye waste water is from2to14, and the membranes may be cleaned by chemical solvent at some time. In this paper, the stability of electrospun PSF membraneand PA6/66membrane in different pH value of hydrochloride and sodium hydroxidesolution, deionized water,1%H2O2and0.5%NaClO were studied, and the wet thermalstability in hot deionized water was also studied. The results showed that190℃-2helectrospun PSF membrane had excellent stability in above solution, and also had excellentthermal stability in deionized water below60℃, but the morphology and porous structureof membrane was damaged seriously after treated in deionized water at80℃for4+4days.So it can be cleaned by the above solution and can be used under60℃for long time. Theelectrospun PA6/66membrane which was treated at90℃for15min under wet condition,had good stability in different pH value of hydrochloride and sodium hydroxide solution,but was damaged seriously in1%H2O2and0.5%NaClO solution, So it can not be cleanedby H2O2and NaClO solution. It has good stability in hot deionized water below40℃, butwas damaged seriously under60℃.In order to improve the hydrophilicity and mechanical property of electrospun PSFmembrane, and also decreased its pore size, so that it can remove dyes, decrease membranefouling and resist larger filtering pressure. The190℃-2h electrospun PSF membrane wastreated by O2plasma at first, then it was padded by chitosan solution crossliked withglutaraldehyde. The results showed that the hydrophilicity and mechanical property of themembrane were both improved significantly, and its pore size was also decreased largely.After the membrane was padded with2%-120crosslinked chitosan solution which meansmass percentage of chitosan was2%and volume of glutaraldehyde was120μl, its poresize was below0.09μm due to partial pores were covered by chitosan, its initial modulusand breaking strength increased by277.2%and126.8%respectively, and its breakingenlongation decreased by86.9%. After the membrane was padded with2%-100crosslinked chitosan solution, its average pore size decreased from4.5μm to2.62μm, itsinitial modulus and breaking strength increased by134.7%and53.9%respectively，and itsbreaking enlongation decreased by77.2%。The filtration property of190℃-2h electrospun PSF membrane,2%-100modified PSFmembrane,2%-120modified PSF membrane and90℃-15min electrospun PA6/66membrane to disperse blue2BLN suspension and weak acid blue N-RL solution wasstudied under dead-end condition. The results showed that the separation factor of2%-120 modified PSF membrane was99.5%, when the concentration of disperse blue2BLNsuspension was0.1g/L under constant pressure0.1MPa, but the filtration flux was greatlysmaller than other membranes. The separate factors of other membranes were similar, allabove94%, and the filtration flux was going to same after filtering for25min. Theseparation factor of2%-120modified PSF membrane was not changed obviously when thefiltration pressure was increased from0.1MPa to0.3MPa. Meanwhile multi-layers couldnot increase the separation factor, and there was not obvious relationship betweenconcentration of disperse blue and separation factor of electrospun PSF membrane. Whenfiltered0.1g/L weak acid blue solution under constant pressure0.1MPa, the separationfactors of190℃-2h electrospun PSF membrane and90℃-15min electrospun PA6/66membrane were all smaller, but the stable filtration flux were similar, which was at45～51L/m2.h. The separation factor of2%-120modified PSF membrane was above92.4%,and the permeated solution was clearer, but the filtration flux was still too small, which isthe main defect of the modified membrane.更多还原