反相气相色谱法研究小分子与聚合物间的溶解扩散行为

发布时间：2018-03-14 04:26

本文选题：无限稀释活度系数　切入点：无限稀释扩散系数　出处：《北京工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：渗透汽化技术具有分离效率高、低能耗等特点,在化工分离、新能源等诸多领域拥有良好的应用前景。膜材料的选择与制备是渗透汽化技术的关键,根据溶解-扩散模型,渗透汽化膜的分离性能主要取决于膜材料与待分离组分间溶解扩散性质的差异。深入研究小分子与聚合物间的溶解扩散行为,将有助于渗透汽化传质机理的研究,同时也是一种有效的膜材料筛选的方法。反相气相色谱技术(Inverse gas chromatography,简称IGC)是一种能够快速、准确测定小分子与聚合物间相互作用的方法。本文利用反相气相色谱技术测定了有机硫/聚磷腈(Polyphosphazenes,简称POPs)体系、醇/聚醚嵌段酰胺(Polyether block amide,简称PEBA)体系间的无限稀释活度系数和无限稀释扩散系数,利用以上数据指导膜材料的选择和制备,解释渗透汽化分离性能。首先测定了353.15-373.15 K下正庚烷、噻吩、2-甲基噻吩、2,5-二甲基噻吩、乙硫醚、正丁硫醇在聚三氟乙氧基磷腈(poly[bis(trifluoroethoxy)phosphazene],简称PTFEP)和聚苯氧基磷腈(Poly[bis(phenoxy)phosphazene],简称PBPP)中的无限稀释活度系数和无限稀释扩散系数。分析了聚磷腈侧链取代基对溶解扩散数据的影响,以及溶解扩散行为与渗透汽化分离性能的关系。PTFEP膜优异的脱硫性能来源于正庚烷和有机硫分子在PTFEP中较大的溶解扩散行为的差异。苯氧基团的引入,增大了有机硫分子在聚磷腈中的无限稀释扩散系数,进而增强了有机硫分子在PBPP中的渗透能力。此外,利用反相气相色谱技术,比较了甲醇、乙醇、正丙醇、正丁醇在PEBA2533和PEBA4033间溶解扩散能力。优选出PEBA2533作为渗透汽化膜材料并用于正丁醇/水体系的分离。制备了PEBA/Poly[vinylidene fluoride](PVDF)复合膜,对于1%的正丁醇水溶液,500C下,复合膜的分离因子为19.5,通量为808.5 g.m-2.h-1。为了进一步提升膜的分离性能,制备了ZIF-8/PEBA杂化膜,当填充量为20%,,对于1%的正丁醇水溶液,500C下,杂化膜的分离因子为24.8,通量为360.5 g.m-2.h-1。
[Abstract]:Pervaporation technology has the characteristics of high separation efficiency and low energy consumption. It has a good application prospect in many fields, such as chemical separation, new energy sources and so on. The selection and preparation of membrane materials is the key of pervaporation technology, according to the dissolution-diffusion model. The separation performance of pervaporation membrane mainly depends on the difference of the dissolution and diffusion properties between the membrane materials and the components to be separated. Further study on the dissolution and diffusion behavior between small molecules and polymers will be helpful to the study of the mechanism of permeation and vaporization mass transfer. Reverse Gas Chromatography (reverse Gas Chromatography) is a rapid method for screening membrane materials. In this paper, the organic sulfur / polyphosphazenes (POPs) system was determined by reversed-phase gas chromatography. The infinite dilution activity coefficient and infinite dilution diffusion coefficient between alcohol / polyether block amide. the above data were used to guide the selection and preparation of membrane materials to explain the pervaporation separation performance. First, n-heptane at 353.15-373.15 K was determined. Thiophene 2-methylthiophene (2-methylthiophene) -5-dimethyl thiophene, ethyl sulfide, The infinite dilution activity coefficient and infinite dilution diffusion coefficient of n-butyl mercaptan in poly [bis(trifluoroethoxy)phosphazene] and bis(phenoxy)phosphazene of poly (trifluoroethoxyphosphonitrile) and polyphenoxyphosphonitrile (bis(phenoxy)phosphazene) were studied. The excellent desulfurization performance of PTFEP membrane comes from the difference of dissolution diffusion behavior between n-heptane and organic sulfur molecules in PTFEP, and the introduction of phenoxy groups. The infinite dilution diffusion coefficient of organic sulfur molecules in polyphosphazene was increased, and the permeability of organic sulfur molecules in PBPP was enhanced. In addition, methanol, ethanol and n-propanol were compared by reverse phase gas chromatography. The solubilization and diffusion ability of n-butanol between PEBA2533 and PEBA4033 was obtained. PEBA2533 was selected as the pervaporation membrane material and used in the separation of n-butanol / water system. The PEBA/Poly [vinylidene fluoride] / PVDF composite membrane was prepared. The separation factor of the composite membrane was 19.5 and the flux was 808.5 g 路m-2.h-1.In order to further improve the separation performance of the hybrid membrane, the ZIF-8/PEBA hybrid membrane was prepared. The separation factor and flux of the hybrid membrane were 24.8 and 360.5 g 路m-2.h-1 for 1% n-butanol aqueous solution at 500C.
【学位授予单位】：北京工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O657.71;TQ021.4

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