磺化聚醚砜正渗透复合膜的制备及其性能研究

发布时间：2018-04-21 00:27

  本文选题：正渗透 + 复合膜　； 参考：《哈尔滨工业大学》2015年硕士论文

【摘要】：正渗透(FO)膜分离技术以其不需外加压力驱动、低能耗、低成本、高回收率、抗膜污染等特点逐渐成为膜分离技术领域研究的热点,目前在多个领域展示了很好的应用前景,得到了一定程度的工程应用。但是FO依然有自身的局限性,这些局限主要涉及以下几个方面:首先,没有方便并且经济地回收或被浓缩的汲取液;其次,FO膜内浓差极化比较严重;此外,溶质反向扩散也是FO过程中一个不可忽视的问题;但是限制FO发展最核心的因素是没有合适的FO膜。因此,研究制备高性能FO膜显得十分有必要,本课题着重研究了支撑层以及聚酰胺活性层的制备条件对高性能磺化聚醚砜正渗透复合膜(SPES-FO膜)性能的影响,同时还研究了错流操作条件对提升SPES-FO膜性能的效果。本课题采用浸没凝胶沉淀相转化法制备SPES-FO膜支撑层,研究了磺化聚醚砜支撑层制备配方及其影响因素。从铸膜液中聚醚砜质量浓度、致孔剂质量浓度、刮膜厚度以及磺化聚醚砜的磺化度这几个因素对支撑层结构的影响展开了相关研究。优化制备条件为:支撑层铸膜液中聚合物质量浓度为16%、致孔剂质量浓度为10%、磺化聚醚砜的磺化度为6%、刮膜厚度为120μm,此时制备出的SPES-FO膜的纯水通量最大,正渗透Na Cl返混通量也较低。利用自制的界面聚合板框在制备的磺化聚醚砜支撑层上进行界面聚合反应生成聚酰胺活性层。分别研究了在不同界面聚合条件下,活性层的结构变化对SPES-FO膜的纯水通量和Na Cl返混通量大小的影响。结果表明,界面聚合最佳热处理时间为30 s,最佳热处理温度为80℃,热处理时间为1 min。若对Na Cl返混通量没有特殊高要求时,不进行热处理时SPES-FO膜的纯水通量最高,此时Na Cl返混通量也达到较理想的水平值,而将水相溶液p H调节到碱性后进行界面聚合,SPES-FO膜性能出现极大的下滑。在不同的错流水温、错流流速、Na Cl汲取液浓度以及不同膜朝向条件下测试了磺化聚醚砜正渗透复合膜的性能,研究不同错流条件对膜性能的影响以优化正渗透膜分离过程的操作条件。研究表明,提高错流水温和错流流速都有利于减缓SPES-FO膜的浓差极化,增大Na Cl溶液浓度虽然在一定程度上加剧了膜内ICP,但是这三者都能提升膜的纯水通量,Na Cl返混通量也会随之升高。在FO模式下,支撑层内发生的稀释型ICP为影响膜性能的主要因素;在PRO模式下,活性层表面发生的稀释型ECP为影响膜性能的主要因素。
[Abstract]:Due to its characteristics of no additional pressure, low energy consumption, low cost, high recovery rate and resistance to membrane fouling, the membrane separation technology has gradually become a hot spot in the field of membrane separation, and has shown a good application prospect in many fields. A certain degree of engineering application has been obtained. However, FO still has its own limitations, which are mainly related to the following aspects: first, there is no convenient and economical recovery or concentration of the solution; secondly, the concentration polarization of FO film is relatively serious; in addition, The reverse diffusion of solute is also an important problem in FO process, but the most important factor limiting the development of FO is the lack of suitable FO membrane. Therefore, it is necessary to study the preparation of high performance FO membranes. In this paper, the effects of the preparation conditions of the support layer and the active layer of polyamide on the performance of the sulfonated polyethersulfone composite membrane (SPES-FO) are studied. At the same time, the effect of cross-flow operation condition on improving the performance of SPES-FO film is also studied. In this paper, SPES-FO membrane supporting layer was prepared by immersion gel precipitation phase inversion method. The preparation formula of sulfonated polyethersulfone support layer and its influencing factors were studied. The influence of the mass concentration of polyethersulfone, the concentration of pore-forming agent, the thickness of scraping membrane and the sulfonation degree of sulfonated polyethersulfone on the structure of the support layer were studied. The optimum preparation conditions are as follows: the polymer concentration in the casting solution of the supporting layer is 16, the mass concentration of the porogenic agent is 10, the sulfonation degree of sulfonated polyethersulfone is 6 and the thickness of the scraping membrane is 120 渭 m. The pure water flux of the prepared SPES-FO membrane is the largest. The remixing flux of normal permeable NaCl is also low. The polyamide active layer was formed by interfacial polymerization on the supported layer of sulfonated polyethersulfone using the self-made interfacial polymerization plate and frame. The effects of the structure of the active layer on the pure water flux and NaCl backmixing flux of SPES-FO membrane were studied under different interfacial polymerization conditions. The results show that the optimum heat treatment time for interfacial polymerization is 30 s, the optimum heat treatment temperature is 80 鈩，

本文编号：1780139