基于界面多重作用调控的超薄膜制备与醇水分离性能强化

发布时间：2018-02-25 06:16

  本文关键词： 界面多重作用 超薄膜 复合膜 杂化膜 溶解-扩散机制 醇水分离　出处：《天津大学》2015年博士论文　论文类型：学位论文

【摘要】：高性能膜材料是提高膜技术竞争力的关键,而膜内界面作用调控是优化膜结构、强化膜传质机制,进而获得高性能膜材料的重要手段。本研究面向燃料乙醇生产这一能源环境领域的重大问题,以超薄膜制备及其醇水分离性能强化为目标,提出了针对膜内不同类型界面的相互作用调控方法及通过界面多重作用调控实现膜传质机制集成优化的策略,采用简便、温和的方法制备了一系列具有适宜化学结构和拓扑结构的超薄复合膜/超薄杂化膜,实现了乙醇/水的高效分离,以期为高性能醇水分离膜的规模化制备提供理论基础与技术支持。主要研究结果如下:分离层-支撑层界面多重作用调控:基于仿生粘合法,将多巴胺和聚乙烯亚胺(PEI)共沉积于支撑层表面后涂覆海藻酸钠制备超薄复合膜。界面区大量的静电引力和氢键作用位点使界面亲水性提高,膜自由体积特性得到改善,实现溶解机制与扩散机制的集成优化,所制备的复合膜渗透通量为1196 g/m2h,分离因子为1807,分离因子较支撑层未改性的复合膜提高29.6倍。分离层-分离层界面多重作用调控:(1)受茶多酚沉淀蛋白质生物现象的启发,基于蛋白质(明胶)和多酚(单宁酸)间的疏水及氢键作用,通过层层自组装过程制备超薄复合膜。界面多重作用的引入可优化膜表面化学组成及多层膜自由体积特性,实现溶解机制与扩散机制的集成优化,所制备的多层膜渗透通量为1336 g/m2h,分离因子为658。在高水含量下可获得更高的分离性能,在原料液水含量为30 wt%时,渗透通量可达2696 g/m2h,透过液中水含量可达99.43 wt%。(2)选择结构匹配的明胶和氧化石墨烯作为组装材料,通过多重作用(静电引力、氢键和疏水作用)驱动的层层自组装过程制备超薄杂化膜。通过调控界面作用强度可优化多层膜拓扑结构,实现扩散机制优化,所制备的多层膜相比于纯明胶膜可实现渗透通量和分离因子的同时提高。高分子-填充剂界面多重作用调控:(1)基于自由基聚合方法制备两性离子接枝改性的氧化石墨烯作为填充剂制备超薄共混杂化膜。两性离子基团的引入可优化杂化膜亲疏性,界面静电引力及氢键的多重作用可优化杂化膜自由体积特性及结晶度,实现溶解机制与扩散机制的集成优化,所制备的杂化膜相比于纯海藻酸钠膜可实现渗透通量和分离因子的同时提高,渗透通量为2140 g/m2h,分离因子为1370。(2)基于金属-儿茶酚螯合作用在TiCl4溶胶凝胶过程中加入改性剂同步改性制备超薄原位杂化膜。改性剂的引入可提高界面亲水基团含量以优化杂化膜亲疏性,可调控界面共价键及氢键作用数量以优化杂化膜自由体积特性及界面结构形态,实现溶解机制与扩散机制的集成优化,所制备的杂化膜渗透通量为1403 g/m2h,分离因子为730。
[Abstract]:High performance membrane material is the key to improve the competitiveness of membrane technology, and the regulation of interfacial action is to optimize the membrane structure and enhance the membrane mass transfer mechanism. In this study, the preparation of ultrathin films and the enhancement of the separation performance of alcohol and water are the main problems in the field of energy environment, especially in the field of fuel ethanol production. In this paper, a method for regulating the interaction between different types of interfaces in the membrane and a strategy for optimizing the mechanism of mass transfer through the regulation of multiple interfacial interactions are put forward, which are simple and convenient. A series of ultrathin composite membranes / ultrathin hybrid membranes with suitable chemical structure and topological structure were prepared by mild method, and the high efficiency separation of ethanol and water was realized. In order to provide theoretical basis and technical support for the large-scale preparation of high performance alcohol-water separation membrane, the main results are as follows: the interface of separation layer and support layer is regulated by multiple interaction: based on bionic bonding method, The ultrathin composite films were prepared by co-deposition of dopamine and polyvinyleneimine (PEI) on the surface of the support layer and then coated with sodium alginate. A large number of electrostatic gravity and hydrogen bond sites in the interface region improved the hydrophilicity of the interface and the free volume characteristics of the membrane. Realize the integration optimization of dissolution mechanism and diffusion mechanism, The permeation flux of the composite membrane was 1196 g / m ~ (2) h, the separation factor was 1807, and the separation factor was 29.6 times higher than that of the unmodified composite membrane. Based on the hydrophobic and hydrogen bond interaction between protein (gelatin) and polyphenol (tannic acid), ultrathin composite films were prepared by layer by layer self-assembly process. The permeation flux of the multilayer membrane was 1336 g / m ~ (2) h, and the separation factor was 658. A higher separation performance could be obtained under the condition of high water content, when the water content of the feedstock liquid was 30 wt%. The permeation flux can reach 2696 g / m ~ 2 h, and the water content in the permeation solution can reach 99.43 wt. t ~ (2).) the structurally matched gelatin and graphene oxide are selected as assembly materials through multiple interactions (electrostatic force, electrostatic force, electrostatic force). The layer by layer self-assembly process driven by hydrogen bond and hydrophobic interaction can be used to prepare ultrathin hybrid films. The topological structure of multilayer films can be optimized and the diffusion mechanism can be optimized by regulating the interfacial interaction strength. The permeation flux and separation factor of the prepared multilayer membrane are higher than that of the pure rubber membrane. Preparation of Amphoteric Ion Graft Modification Oxidation based on Free radical Polymerization. Ultrathin blend hybrid membranes were prepared by using graphene as filler. The introduction of amphoteric groups can optimize the affinity of hybrid membranes. The free volume characteristics and crystallinity of hybrid membranes can be optimized by the interaction of interfacial electrostatic force and hydrogen bond, and the integration of dissolution mechanism and diffusion mechanism can be realized. Compared with the pure sodium alginate membrane, the hybrid membrane can realize the increase of permeation flux and separation factor at the same time. The permeation flux was 2140g / m ~ (2 h) and the separation factor was 1370.2.Based on the metal-catechol chelation process, the ultrathin in-situ hybrid membrane was prepared by simultaneous modification with modifier in the process of TiCl4 sol gel. The introduction of modifier can increase the content of hydrophilic group at the interface. In order to optimize the affinity of hybrid membrane, The amount of interfacial covalent bond and hydrogen bond can be adjusted to optimize the free volume characteristic and interface structure of hybrid membrane, and to realize the integration optimization of dissolution mechanism and diffusion mechanism. The permeation flux of the hybrid membrane is 1403 g / m ~ (2) h and the separation factor is 730 g / m ~ (2) h.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TQ051.893
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本文编号：1533316