分子自组装制备二氧化碳气体分离膜

发布时间：2018-06-14 17:42

  本文选题：促进传递膜 + 二氧化碳分离　； 参考：《浙江工业大学》2017年硕士论文

【摘要】：CO2是造成全球变暖的一种主要温室气体,且会降低沼气、天然气等燃气的燃烧值,腐蚀运输管道等。因此,分离和回收CO2气体对环境和能源都具有非常重要的意义。目前商业化的CO2气体分离方法中,膜分离法因其设备简单、高效灵活、易于操作、投资低等优点而得到越来越多的关注。制备气体分离膜的方法有很多,但是用一种绿色、简单、高效的方法制备CO2气体分离膜,仍具有很大的挑战。本文采用静电自组装的方法制备兼具高渗透性和高选择性的CO2促进传递膜,选用低浓度的聚乙烯亚胺(PEI)水溶液作为自组装溶液,商业化的聚酰胺(PA)反渗透膜为底膜。文中对影响自组装膜性能的因素,包括膜的干湿态、自组装方式、PA底膜、自组装层数、自组装时间、进料压力、各种自组装条件等进行了研究,并对膜进行了场发射扫描电子显微镜(SEM)、傅里叶变换红外光谱(FT-IR)、X射线光电子能谱(XPS)、接触角等的表征。为了使这种制备方法更具有实用性,由对膜片的自组装,扩大到对膜组件的自组装。(1)在PEI水溶液浓度50 mg/L,pH值8.0,动态自组装,自组装泵压0.6MPa,操作温度25℃,自组装时间1 h条件下,制得的膜具有较高的气体渗透速率和选择性。PEI分子在底膜上的吸附,只需有几十秒就能达到吸附平衡,且单层自组装比多层自组装更具有优势。(2)CO2透过自组装膜的传递是聚合物链间增加的自由体积和PEI分子(和H2O分子)的促进传递两方面因素共同作用的结果,而N2的传递仅仅只是溶解-扩散的结果。(3)SEM、XPS以及接触角分析结果均可以证明膜表面沉积有PEI分子,但是由于自组装的PEI溶液浓度极低,且为单层自组装,膜表面PEI分子数量很少,因此SEM断面图和FT-IR表征均得不到关于组装的有用信息。(4)将静电自组装的制膜方法,从面积为25 cm2的膜片放大到0.5 m2和1.3m2的卷式膜组件,得到的膜组件仍具有较高的气体分离性能,并且将组件烘干后浸润,组件气体分离性能基本保持不变,说明这种制备方法易于放大,所得膜性能稳定,不易被破坏,具有很好的实用价值。
[Abstract]:CO2 is one of the main greenhouse gases that cause global warming, and it will reduce the burning value of biogas, natural gas and so on, and corrode the transportation pipeline and so on. Therefore, the separation and recovery of CO2 gas is of great importance to the environment and energy. Among the commercial CO2 separation methods, membrane separation has attracted more and more attention because of its advantages of simple equipment, high efficiency and flexibility, easy operation and low investment. There are many methods to prepare gas separation membrane, but it is still a challenge to prepare CO2 gas separation membrane by a green, simple and efficient method. In this paper, a high permeability and high selectivity CO2 promoted transfer membrane was prepared by electrostatic self-assembly. A low concentration polyethylene imide (PEI) aqueous solution was used as the self-assembly solution, and a commercial polyamide (PAA) reverse osmosis membrane was used as the base membrane. In this paper, the factors affecting the properties of the self-assembled films, including the dry and wet state of the films, the self-assembly mode of PA substrate, the number of self-assembled layers, the self-assembly time, the feed pressure, the various self-assembly conditions, etc. The films were characterized by field emission scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and contact angle. In order to make the preparation more practical, the self-assembly of the membrane was expanded from the self-assembly of the membrane to the self-assembly of the membrane assembly. The pH value of PEI solution was 50 mg / L ~ (-1), the dynamic self-assembly, the pump pressure of self-assembly was 0.6 MPA, and the operating temperature was 25 鈩，

本文编号：2018419