高分子—金属有机框架杂化膜的制备与渗透蒸发过程强化

发布时间：2018-04-24 23:03

本文选题：杂化膜 + 金属有机框架材料　；参考：《天津大学》2016年博士论文

【摘要】：近年来,空气污染问题已成为全社会关注的热点问题,车用燃油脱硫是降低空气污染物排放量的有效手段之一。渗透蒸发脱硫过程具有效率高、能耗物耗低、环境友好等特点,具有良好应用前景。渗透蒸发脱硫过程是高溶胀性有机小分子混合物分离的典型过程,开发兼具高渗透性、高选择性、高稳定性的膜材料是实现渗透蒸发脱硫过程高效强化的关键,然而现有的膜材料难以满足前述需求。本研究面向清洁燃油生产的重大需求,设计制备一系列兼具高渗透性、高选择性、高稳定性的高分子-金属有机框架材料(MOF)杂化膜,调控构效关系,实现模拟汽油脱硫过程的高效强化,以期为高性能脱硫膜材料的开发提供理论与技术层面的参考。1.为调控膜的自由体积特性并利用MOF的规整孔道结构提高膜的渗透性,将具有发达孔道结构的MIL-101引入聚二甲基硅氧烷(PDMS)膜基质制备了杂化膜。MIL-101通过干扰PDMS链段排布提高膜的自由体积分数,提高膜的渗透性,并在膜内提供了低阻力传质通道。所制备的杂化膜与PDMS空白膜相比,渗透通量与富集因子分别提高136%与38%。2.为调控高分子-填充剂界面,将负载Cu(II)的UiO-67-bpydc引入PDMS膜基质制备了杂化膜。负载的Cu(II)可改变UiO-67-bpydc的结构,影响高分子-填充剂界面附近高分子链段的排布,提高膜的渗透性。所制备的杂化膜与不负载Cu(II)的PDMS-UiO-67-bpydc杂化膜相比,渗透通量提高54%,选择性未见显著变化;与PDMS空白膜相比,渗透通量与选择性分别提高74%与10%。3.为明确MOF的孔道与通过干扰高分子链段排布提高膜自由体积分数这两种因素各自对膜渗透性提高的贡献,并在渗透蒸发模拟汽油脱硫过程中引入促进传递机制,实现膜分离过程的溶解选择性、扩散选择性、反应选择性的协同优化,将具有空金属活性位的CuBTC(HKUST-1)与参照物闭孔CuBTC分别引入PDMS基质制备了杂化膜。CuBTC的空金属活性位发挥促进传递作用。所制备的填充CuBTC与闭孔CuBTC的杂化膜与空白膜相比,标准化渗透通量、富集因子分别提高100%、75%与47%、7%。4.为调控高分子链段间的相互作用,提高膜的渗透性,将CuBTC引入Pebax2533膜基质制备了杂化膜。CuBTC通过干扰高分子链段间的相互作用并与高分子链段形成氢键作用来调控膜结构,提高膜的渗透性与稳定性;通过促进传递作用提高膜的选择性。所制备的杂化膜与Pebax空白膜相比,渗透通量与富集因子分别提高36%与11%,且在较高操作温度下的分离性能具较大的竞争优势。
[Abstract]:In recent years, air pollution has become a hot issue in the whole society, and vehicle fuel desulfurization is one of the effective means to reduce the emissions of air pollutants. The process of osmotic evaporation desulphurization has the advantages of high efficiency, low energy consumption and environmental friendliness, so it has a good prospect of application. The process of osmotic evaporation desulfurization is a typical process of separation of high swelling organic small molecule mixtures. The development of membrane materials with high permeability, high selectivity and high stability is the key to realize the high efficiency strengthening of osmotic evaporation desulfurization process. However, the existing membrane materials are difficult to meet the above requirements. In this study, a series of MOF hybrid membranes with high permeability, high selectivity and high stability were designed to control the structure-activity relationship for the important demand of clean fuel production. In order to provide theoretical and technical reference for the development of high performance desulfurization membrane materials, the simulated gasoline desulfurization process can be strengthened efficiently. In order to control the free volume characteristics of the membrane and improve the permeability of the membrane by using the regular pore structure of MOF, The hybrid membrane, MIL-101, was prepared by introducing MIL-101 with developed pore structure into polydimethylsiloxane (MIL-101) membrane matrix. The hybrid membrane. MIL-101 improved the free volume fraction and permeability of the membrane by interfering with the arrangement of PDMS segments, and provided a low resistance mass transfer channel in the membrane. Compared with the PDMS blank membrane, the permeation flux and enrichment factor of the hybrid membrane were increased by 13.6% and 38.2, respectively. In order to control the polymer-filler interface, the hybrid membrane was prepared by introducing the UiO-67-bpydc loaded with Cu II into the substrate of PDMS membrane. The structure of UiO-67-bpydc can be changed by supported Cui II, and the arrangement of polymer chain near the polymer filler interface can be affected, and the permeability of the membrane can be improved. The osmotic flux of the hybrid membrane was increased by 54% and the selectivity of the hybrid membrane was increased by 74% and 10. 3%, respectively, compared with that of the unloaded PDMS-UiO-67-bpydc hybrid membrane, and the osmotic flux of the hybrid membrane was increased by 74% and 10. 3%, respectively, compared with that of the PDMS blank membrane. In order to clarify the contribution of the pore channel of MOF and the increase of free volume fraction of membrane by interfering with the arrangement of polymer chain, the mechanism of promoting transport was introduced in the process of desulfurization of simulated gasoline by permeation evaporation. The solution selectivity, diffusion selectivity and reaction selectivity of membrane separation process were optimized. The empty metal active sites of the hybrid film. CuBTC were prepared by introducing the closed pore CuBTC into the PDMS substrate. The active site of the hybrid film. CuBTC played a role in promoting the transfer. Compared with the blank membrane, the standard osmotic flux and enrichment factor of the hybrid membrane filled with CuBTC and closed pore CuBTC were increased by 100% and 75%, respectively. In order to regulate the interaction between polymer segments and improve the permeability of the membrane, the hybrid membrane 路CuBTC was prepared by introducing CuBTC into the Pebax2533 membrane matrix to regulate the membrane structure by interfering the interaction between the polymer segments and forming a hydrogen bond with the polymer segment. The permeability and stability of the membrane were improved, and the selectivity of the membrane was improved by promoting the transport. The permeation flux and enrichment factor of the hybrid membrane were increased by 36% and 11%, respectively, compared with the Pebax blank membrane, and the separation performance of the hybrid membrane at higher operating temperature was more competitive.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TE624.5;TQ051.893

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