仿生分离材料的制备及其在染料废水净化中的应用

发布时间：2018-05-30 08:08

本文选题：水净化 + 吸附　；参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：随着水资源短缺和水污染的问题日益严峻,能够高效应用于净化及分离水中有机污染物的方法和材料越来越受到人们的关注。吸附和膜分离法因其耗能少、分离效率高等优点在净化水中有机污染物方面具有优势。因此研究开发高效的吸附剂和膜材料能够有效地解决世界性水资源短缺的问题。本研究首先利用较为廉价的类多巴物质没食子酸(GA)与阳离子型聚电解质聚乙烯亚胺(PEI)的共聚合反应,制备以磁性Fe3O4为载体,交联的GA/PEI层为吸附层的Fe3O4@GA/PEI磁性吸附材料,并探究了其在去除水中有机污染物的应用。通过透射电子显微镜(TEM)、傅里叶变换红外光谱(FT-IR)、X射线光电子能谱(XPS)、Zeta电位仪、热失重分析仪(TGA)等对所制备Fe3O4@GA/PEI的物理和化学结构进行了系统全面的表征,并测试了其对不同染料的吸附能力。研究表明,当PEI与GA的质量比为3:2,反应时间为9 h时,所制备的Fe3O4@GA/PEI磁性吸附材料具备最优的染料吸附的能力。其对阴离子型染料甲基蓝和孟加拉玫瑰红的吸附容量分别可达243.5 mg·g-1与190.2mg·g-1。但其对阳离子型染料的吸附效果较差,制约了其在染料废水净化中的应用。受贝壳二维层状堆叠结构的启发,本研究利用PEI交联氧化石墨烯(GO)纳米片,并通过热还原的方法制备了具有类贝壳二维堆叠结构的高通量RGOPEI超薄复合纳滤膜。通过扫描电子显微镜、水接触角测试、傅里叶变换红外光谱测试、X射线光电子能谱测试、Zeta电位仪等对制备的RGOPEI复合纳滤膜进行了物理和化学结构的表征。通过调节PEI的分子量、PEI浓度和GO浓度,考察了不同条件下GO和PEI共同组装过程中的结构和性能的变化,对新型纳滤膜的分离性能进行了表征。测试表明,RGOPEI膜具有极高的水通量和较高的对有机分子的截留率。当PEI分子量为1800 g mol-1,GO浓度为2.5mg L-1,PEI浓度为0.2 g L-1时,所制备的RGOPEI膜纯水通量高达95.8 L m-2h-1 bar-1,对阳离子型染料维多利亚蓝B(VB)和阴离子型染料甲基蓝(MB)的截留率均可达到99.9%以上,具备良好的去除水中染料分子的能力。同时,RGOPEI膜具备良好的水中稳定性和耐酸碱能力,因而其可以在污染严重的水中连续长时间使用。
[Abstract]:With the problems of water shortage and water pollution becoming more and more serious, more and more attention has been paid to the methods and materials that can be used to purify and separate organic pollutants in water efficiently. Adsorption and membrane separation have advantages in purifying organic pollutants in water because of their advantages of low energy consumption and high separation efficiency. Therefore, the research and development of efficient adsorbents and membrane materials can effectively solve the problem of water shortage in the world. In this study, the polyelectrolyte polyimide (PEI) was prepared by the copolymerization of the cheap dopa-like substance, Gallic acid, and the cationic polyelectrolyte polyethyleneimide (PEI). The Fe3O4@GA/PEI magnetic adsorption materials were prepared with magnetic Fe3O4 as the carrier and the cross-linked GA/PEI layer as the adsorption layer. Its application in the removal of organic pollutants in water was also explored. The physical and chemical structures of Fe3O4@GA/PEI were systematically and comprehensively characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analyzer (TGA). The adsorption ability of different dyes was tested. The results show that when the mass ratio of PEI to GA is 3: 2 and the reaction time is 9 h, the prepared Fe3O4@GA/PEI magnetic adsorption material has the best dye adsorption ability. The adsorption capacities for anionic dye methyl blue and Bengal rose red were 243.5 mg g ~ (-1) and 190.2mg g ~ (-1), respectively. However, the adsorption efficiency of cationic dyes is poor, which restricts their application in dye wastewater purification. Inspired by the structure of shell two-dimensional layered stacking, a high-throughput RGOPEI ultrathin composite nanofiltration membrane with shell-like two-dimensional stacking structure was prepared by using PEI crosslinked graphene oxide (GOO) nanoparticles and thermal reduction method. The physical and chemical structures of RGOPEI composite nanofiltration membranes were characterized by scanning electron microscopy (SEM), water contact angle measurement, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). By adjusting the molecular weight and go concentration of PEI, the changes of structure and properties in the process of co-assembly of go and PEI under different conditions were investigated, and the separation performance of the novel nanofiltration membrane was characterized. The results show that RGOPEI membrane has very high water flux and high rejection rate to organic molecules. When the molecular weight of PEI was 1800 g mol ~ (-1) 2.5mg L ~ (-1), the pure water flux of the RGOPEI membrane was up to 95.8 L m-2h-1 bar-1, and the rejection rate for the cationic dye Victoria blue and anionic dye methyl blue was over 99.9%. Good ability to remove dye molecules from water. At the same time, the RGOPEI membrane has good water stability and acid-alkali resistance, so it can be used continuously in seriously polluted water for a long time.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703;TQ051.893

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