【作者】 申利国；

【导师】 陆晓峰；

【作者基本信息】 中国科学院研究生院（上海应用物理研究所） ， 无机化学， 2014， 博士

【摘要】 随着经济社会的高速发展，环境污染和环境破坏问题日益突出，并制约了整个社会的可持续发展。膜分离技术做为一种先进的水处理技术，在环境保护方面发挥着越来越大的作用。然而在实际应用中，高分子膜会受到污染的问题，对膜进行频繁的清洗，不仅费时耗工，而且还会对膜造成损害，这样会严重影响膜的实际应用，对膜进行改性以提高膜的性能显得非常必要，因此本文针对膜污染这一问题，试图通过对膜进行改性研究，包括共混改性和表面改性，从而达到提高膜的抗污染性的目的。在共混改性实验中，通过相转换法制备了ZnO/聚醚砜（PES）复合膜，并与PES膜进行对比研究，考察ZnO/PES膜的热稳定性、亲水性、渗透性能和抗污染能力。结果显示ZnO/PES复合膜的抗污染性提高。随着ZnO添加量增加，膜的水接触角持续降低，而其分解温度逐渐增大。ZnO添加量为0.0500g/g时，水接触角降低到54.86°，而此时膜的热分解温度比PES膜提高了94.4℃。添加了ZnO的复合膜孔隙率增大。添加了ZnO的复合膜水通量提高，而截留率基本无变化。ZnO添加量为0.0250g/g时水通量为最大值125.40kg/m2h，比PES膜的通量提高了254%。连续过滤BSA溶液（1g/L，pH=7.4）90min后，ZnO添加量为0.0375g/g的复合膜通量衰减率为7.8%，而PES膜通量衰减率为27.7%，可见ZnO/PES复合膜具有更高的抗污染性。在水表面上，通过LB膜技术研究了成膜过程中Cu2+对磷脂（DPPC、DPPG、DPMC和DMPG）的影响。结果显示，在成膜过程中对不带电的DPPC，DMPC没有影响，而对于带负电的DPPG和DMPG分子有影响。进一步实验显示，Cu2+和DMPG之间存在强烈相互作用，Cu2+改变了成膜过程中DMPG的相变压力。低浓度的Cu2+溶液导致DMPG压缩性膜，而高浓度的Cu2+溶液导致扩张的DMPG膜。在水表面上，由于DMPG分子之间的静电排斥作用，在相变区域形成树枝状微区。而在Cu2+溶液表面上，静电作用被消除，DMPG形成圆片状微区。同样由于静电作用，在水表面上形成的DMPG膜中具有不均一性，而在Cu2+溶液表面上形成的DMPG膜平整均一。在LB膜技术的基础上，采用层层（LBL）自组装技术对膜表面进行涂覆改性，制备了聚电解质/PES复合膜，并研究了其性能。通过在PES膜表面修饰亲水且带电的聚电解质，以达到提高膜的抗污染性的目的。通过层层（LBL）自组装技术对聚醚砜（PES）微滤膜进行表面涂覆改性。以29.2g/L NaCl做为支撑电解质，在膜表面涂覆一层聚二烯丙基二甲基氯化铵（PDADMAC）-聚苯乙烯磺酸钠（PSS）得到聚电解质/PES复合膜。结果显示聚电解质/PES复合膜表面负电性增加，由PES膜的-4.13mV变为-35.02mV，水接触角降低，由PES膜的59.86°降低到37.99°；膜的表面形貌表征显示，改性后的聚电解质/PES复合膜表面更加平整，孔径尺寸分布更加均一；过滤0.02g/L腐殖酸溶液120min后，PES膜的通量下降了39.4%，而改性后的聚电解质/PES复合膜通量下降了15.5%，可见聚电解质/PES复合膜具有更高的抗污染性。更多还原

【Abstract】 As the fast developing of economic society, environment was being polluted anddamaged terribly. This phenomena slacks the continuable development of the wholesociety. Membrane separation technology as an advanced water treatment technology,is playing a more and more important role in environmental protection. However, inpractical application, the polymer membranes are easy to be polluted, which seriouslyaffects the membrane performance. As to this problem, in this paper, the PESmembrane was modified by blending and surface coating methods.In the experiment process, ZnO/PES composite membrane was prepared byphase inversion method. By comparing with the PES membrane, the properties ofZnO/PES composite membrane were investigated. The Langmuir-Blodgett (LB)technique was learnt. The phospholipid membranes were prepared by LB technique.The effects of Cu2+on phospholipid membranes were investigated. Layer-by-layerself-assembly (LBL) developed from LB technique was used to modify PESmembrane. The properties of prepared polyelectrolyte/PES composite membraneswere investigated.With ZnO as an additive, a series of ZnO/PES composite membranes wereprepared by a phase-inversion method. Experimental results show that, with theincreasing of addition weight of ZnO the contact angle decreases and the thermodecomposition temperature increases. When the addition of ZnO is0.0500g/g, thewater contact angle is54.86°and the thermal decomposition tempureture is improvedby94.4℃.The porosity of ZnO/PES hybrid membrane is improved by adding ZnO.The flux of ZnO/PES composite membrane reached to125.40kg/m2h, which exhibitsan improvement of254%relative to that of the PES membrane, whereas the rejectionchanges little. After90min of continuous filtrating of BSA solution (1g/L, pH=7.4), the decreased flux ratio of the ZnO/PES membrane (0.0375g/g ZnO added) is only7.8%, which implies the antifouling property is significantly improved relative to theantifouling property of the PES membrane.The effects of Cu2+on phospholipid (DPPC, DPPG, DMPC and DMPG) at theair/water interface were studied by a Langmuir film balance. The results show thatCu2+ions interact strongly with the negatively charged DMPG. This interactionchanges the phase transition pressure from the LE (liquid-expanded) to the LC(liquid-condensed) state. The introduction of low concentration Cu2+leads to largelyincreased ionic strength, which causes to an expansion of the DMPG membrane.However, high concentration of Cu2+tends to lower pH. The decreased pH and thedirect binding between Cu2+and DMPG together induced a condensed effect onDMPG membrane. The phase transition pressure decreases with the increasingconcentration of Cu2+. The electrostatic repulsion drives DMPG to plant-branch shapedomains. While on the Cu2+solution, the electrostatic repulsion is largely weakened,and circular shape domains appear. Because of strong electrostatic repulsion, the finalmembrane on water subphase is less uniform than that on Cu2+solution subphase.The PES microfiltration membrane was modified by the layer by layerself-assembly (LBL) method. To obtain polyelectrolyte/PES composite membrane,29.2g/L NaCl as a support electrolyte solution, one layer ofdiallyldimethylammonium chloride (PDADMAC)/polystyrene sulfonate (PSS) wascoated onto the PES surface. The result shows that the surface of compositemembrane charges more negatively. The charge value is-35.02mV. The water contactangle decreased from59.86°for PES membrane to37.99°for the compositemembrane. The surface morphology shows that the surface of composite membrane issmoother, and the pore size distribution is more uniform. Filtrating of0.02g/L humicacid in120min, the decreased flux rate of PES membrane is39.4%, while thedecreased flux rate for the composite membrane is15.5%. The composite membraneshow higher antifouling ability.更多还原