【作者】 王安娜；

【导师】 顾瑾；

【作者基本信息】 江南大学 ， 化学工程， 2012， 硕士

【摘要】 为了改善分子筛Silicalite-1与聚酰胺（PA）之间的相容性,减少膜内非选择性的缺陷,本文采用双酚A型环氧树脂（简称BE188）对分子筛纳米颗粒表面进行改性,并通过界面聚合将其添加到PA层中制备了Silicalite-1/PA杂化膜,再进一步地研究了该杂化膜的分离性能、耐氯性、荷电性、化学稳定性以及耐污染性等。首先以双酚A型环氧树脂作为改性剂,氯化亚锡作为催化剂,通过环氧基团与硅醇键的开环反应,对Silicalite-1分子筛纳米颗粒表面进行改性,接枝有机短链,并通过FTIR、1H-NMR、EDX、XRD、TEM测试等对改性前后的Silicalite-1分子筛进行表征,结果证实分子筛表面成功接枝上有机短链。改性后的分子筛亲油性提高,在界面聚合油相溶剂正己烷中分散性提高,团聚现象得到改善。将改性分子筛添加到油相中通过界面聚合制备反渗透杂化膜。添加改性分子筛后,杂化膜不但维持较高的亲水性,而且膜的荷负电性提高。TEM表征结果证明:分子筛经表面改性后,不但提高了在PA基质中的分散性,而且与PA基质之间的相容性也有明显改善,从而减少了界面缺陷。由SEM表征结果可知:分子筛的表面改性对杂化膜表面形貌的影响较小。将所制备的膜用于2000 ppm NaCl水溶液反渗透脱盐,发现改性Silicalite-1/PA杂化膜的分离性能优于未改性Silicalite-1/PA杂化膜;且当改性分子筛的添加量为0.1%时,膜的水通量为38.72 L·m^-2·h^-1,约是PA膜通量的1.5倍,同时膜的截留率也有所提高。最后,考察了含改性分子筛杂化膜的耐氯性、化学稳定性、BSA吸附量以及耐BSA污染能力。全硅型分子筛Silicalite-1表面的有机短链有助于提高反渗透膜的耐酸性,其表面的苯环减少了氯对聚酰胺的取代,使得膜结构没有遭到严重破坏。所以采用BE188对分子筛表面进行有机化改性,对于防止聚酰胺膜的氯化起到了一定的作用。由于改性杂化膜的Zeta电位较低,膜表面与水和盐离子的静电排斥作用较强,使其在测试的pH范围内一直保持较高的截留率,而膜通量几乎保持不变。将改性分子筛填充于聚酰胺膜后,不但提高了膜的化学稳定性,同时也提高了膜的耐蛋白质污染性能,延长了反渗透膜的运行时间。更多还原

【Abstract】 In order to improve the compatibility between Silicalite-1 zeolite and polyamide (PA), and reduce non-selective voids, zeolite nanoparticles are modified by the diglycidylether of bisphenol-A with commercial code BE188 (epoxy equivalentweight, EEW = 188). Hybrid membranes are fabricated by interfacial polymerization in the presence of zeolites.Further research of the separation performance, the chlorine resistance , the electrical charge, the chemical stability, and the anti-fouling of resulted membranes are investigated too.Firstly, the surface of the silicalite-1 zeolite nanoparticles is modified by a ring-opening reaction between the epoxy group of BE 188 and the silanol of zeolite under the catalysization of stannous chloride. Then, original and modified silicalite-1 zeolites are characterized by IR, 1H-NMR, EDX, XRD and TEM. The results confirm that the organic shortchain was grafted on the zeolite surface successfully. Moreover, the dispersibility in n-hexane and the hydrophobicity of modified zeolite are improved.The hybrid reverse osmosis membrane is prepared by an interfacial polymerization between MPD and TMC with zeolite. After adding the modified zeolite, the hybrid membranes not only maintain a high hydrophilic, but also an increased negative charge. From TEM images, it has been found that the dispersibility of zeolite in PA matrix increases and the compatibility between them is improved too. The prepared membranes are used for reverse osmosis desalination with 2000ppm NaCl aqueous solution. The separation performance of hybrid membranes filled with modified zeolite is better than the ones filled with original zeolite. When the loading of modified zeolite is 0.1%, the flux is 38.72 L·m-2·h-1, which is ca. 1.5 times as much as that of bare PA membrane, and the rejection improves as well.Finally, the investigation of the hybrid membranes with modified zeolite is carried out, containing the chlorine resistance , the chemical stability, anti-fouling of BSA. The organic shortchain on modified silicalite-1 zeolite surface can improve the acid resistance of the reverse osmosis membrane. The benzene ring of the modified zeolite surface reduces the replacement of chlorine to the polyamide matrix, making membranes structure are not seriously damaged. Therefore, the use of BE188 plays a certain role to prevent the chlorination of polyamide membrane. As the Zeta potential of the hybrid membrane loaded modified zeolite is lower than that of membrane loaded original zeolite, the electrostatic repulsion is strongger between the membrane surface and hydrated salt ions, which makes them maintaining high rejection in the test pH range , while the flux remained almost unchanged. The chemical stability of the polyamide membranes filled with modified zeolite is improved, and the performance of the resistance to protein contamination enhanced at the same time, extending the running time of the reverse osmosis membrane.更多还原