CAS OpenIR  > 研究所(批量导入)
Thesis Advisor张香平
Degree Grantor中国科学院研究生院
Degree Discipline化学工程
Keyword气体分离膜 离子液体共混膜 醚基功能化离子液体 Co2分离

随着大气中CO2含量急剧增加,CO2分离捕集在能源及环境领域日益受到重视。由于具有不易挥发、结构可调及优良的CO2溶解性等优点,离子液体在CO2分离方面拥有巨大潜力。膜法分离法因其设备简单紧凑、能耗低和环境友好等特点,在CO2分离领域具有广泛的应用前景。将离子液体与膜分离方法相结合,既能克服离子液体的高黏度以及高成本等问题,又可利用离子液体对CO2的高亲和性提高膜材料的离性能。本研究设计并制备了一系列功能化离子液体共混膜,对其进行了表征,并考察了该材料对CO2 分离性能的影响规律。论文主要研究内容和结果如下:1) 设计并制备了一系列醋酸纤维素+醚基吡啶离子液体共混膜(CA + [EnPy][NTf2])。物化性质表征结果表明:[E1Py][NTf2]与CA间无化学作用;CA + [E1Py][NTf2]共混膜的热稳定性较好;随着[E1Py][NTf2]含量增加,机械性能和玻璃态温度均下降,说明在CA + [E1Py][NTf2]共混膜中,[E1Py][NTf2]起到了增塑作用。2) 实验研究了CA + [E1Py][NTf2]共混膜的CO2分离性能,结果表明随着[EnPy][NTf2]离子液体含量增加,CO2在CA + [E1Py][NTf2]共混膜中的渗透系数提高了7倍,CO2/N2有所增加,CO2/CH4略有下降,这主要是因为共混膜的CO2选择性取决于[E1Py][NTf2]对膜的增塑作用和对气体亲和性。此外,研究表明原料气中微量水分不利于CA + [E1Py][NTf2]共混膜分离CO2。3) 对比了四种不同CA + ILs共混膜CO2分离性能,结果表明离子液体中醚基的引入有利于提高共混膜的CO2选择性,但CO2渗透性有所下降;而阳离子上烷基链越长,CO2渗透系数越高,CO2/N2及CO2/CH4选择性越低。4) 为了提高Matrimid聚酰亚胺膜的气体渗透性能,采用了两步合成法在聚酰亚胺上原位合成了离子液体侧基。采用红外、核磁等表征手段证明了合成的膜材料结构,结果表明离子液体侧基的功能改性有助于提高N2和CH4的渗透系数,CH4/N2选择性有所提高。

Other Abstract

The efficient separation of CO2 has received growing attentions in energy, environment, since the CO2 concentration in air has substantial increased. Ionic liquids (ILs) have been attracting rising interest owing to their special properties, such as negligible vapor pressure, tunability for targeted applications, and in particular the inherent solubility for CO2. On the other hand, membrane separation is a promising technology for CO2 capture due to less equipment space, lower energy cost and more environmentally friendly. To overcome high viscosity and high cost of ILs and improve the gas separation performance of membranes, immobilization of ILs in membranes has been extensively investigated in recent years. In this study, new ILs membranes were developed, and the physicochemical properties and gas separation performance of IL membranes were evaluated. The major work and main results are as follows:1) A series of composite membranes composed of ether-functionalized pyridinium-based ionic liquids ([EnPy][NTf2]) and cellulose acetate (CA) polymer have been designed and prepared. The physicochemical properties and microstructure of the composite membranes were characterized. The FTIR results showed there is no chemical interaction between [E1Py][NTf2] and CA. The CA + [E1Py][NTf2] composite membranes exhibit good thermal stability. But the mechanical properties and the glass transition temperature (Tg) of the CA + [E1Py][NTf2] composite membranes decrease compared with pure CA membranes, which indicates that [E1Py][NTf2] acts as a plasticizer in the CA + [E1Py][NTf2] composite membrane. 2) CO2, N2 and CH4 permeabilities of the CA + [E1Py][NTf2] composite membranes were measured and the permselectivities were determined by the ratios of the permeabilities of two gases. The results showed that with [E1Py][NTf2] content increasing, CO2 permeability of CA + [E1Py][NTf2] composite membrane increases. And CO2 permeability of CA + 40[E1Py][NTf2] composite membrane exhibits a seven-fold increase. CO2/N2 permselectivity improved and CO2/CH4 permselectivity decreases. The reason of that result is CO2 permselectivities are jointly influenced by plasticizing effect and the affinity of ILs for the gases. Besides, the water in feed gas is unfavorable for CO2 separation performance of the CA + [E1Py][NTf2] composite membrane.3) Compared with four CA + ILs composite membranes, the addition of ether-functionalized [EnPy][NTf2] IL to composite membranes can improve the ideal permselectivities of CO2/N2 and CO2/CH4, whereas decreases slightly gas permeabilities. And the composite membranes with longer alkyl chain tethered to IL have a higher CO2 permeability, and lower ideal permselectivities of CO2/N2 and CO2/CH4.4) To improve the gas permeability of Matrimid membrane, a two-step method is proposed to in-situ synthesize IL-grafted Matrimid membranes. The FTIR and 1H NMR results verified the synthesis method and the structure of the new membrane. The results showed that N2 and CH4 permeabilies increase, but the CO2 permselectivities decrease. 

Document Type学位论文
Recommended Citation
GB/T 7714
邓靓. 新型醚基离子液体复合膜材料制备及CO2分离性能研究[D]. 中国科学院研究生院,2016.
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