Abstract:

Among the commonly used methods to improve the performance of composite films, interfacial polymerization (IP), a key step to regulate the formation of composite films, is a simple and effective method, however, the influence of deep eutectic solvents in the process of interfacial polymerization is relatively rare, and a polyamide composite reverse osmosis membrane is prepared by introducing deep eutectic solvents (DES with a molar ratio of 1∶2) into the interfacial polymerization process. The structure and physicochemical properties of composite films were characterized by Fourier infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (SEM) and atomic force microscopy (AFM). The effect of DES addition on the performance of reverse osmosis membrane was investigated, and the effect of viscosity on the diffusion rate of amine monomer was systematically analyzed. When the DES addition amount was 5%, the composite membrane had the best comprehensive performance, with a flux of 63L/(m²·h) and a retention rate of 99%. The results showed that the incorporation of DES reduced the surface roughness, hydrophilicity and electronegativity, and increased the flux of the composite reverse osmosis membrane modified by DES compared with the unmodified composite membrane. This work was of great significance for the preparation of high-performance composite membranes.

Key words: membranes, polymerization, diffusion, deep eutectic solvents (DES), reverse osmosis

摘要：

在常用的提高复合膜性能的方法中，调控复合膜形成的关键步骤界面聚合（IP）是一种简单且有效的方法。然而，对低共熔溶剂在界面聚合过程中的影响研究相对较少，在此，本文提出了将低共熔溶剂（DES）引入界面聚合过程中，制备了聚酰胺复合反渗透膜。采用傅里叶红外光谱（FTIR）、X射线光电子能谱（XPS）、场发射扫描电镜（SEM）和原子力显微镜（AFM）等对复合膜的结构和物化性质进行了表征。考察了DES的加入量对反渗透膜性能的影响，并系统地分析了黏度对胺单体扩散速率的影响。得出了DES添加量为5%时，复合膜综合性能最佳，通量为63L/(m²·h)，截留率为99%。研究结果表明：DES的掺入使膜表面粗糙度降低、亲水性和电负性增强，此外，相比于未改性的复合膜，DES改性后的复合反渗透膜通量都有所提升。这项工作对制备出高性能的复合膜具有重要意义。

关键词: 膜, 聚合, 扩散, 低共熔溶剂, 反渗透