纳米粒子均一分散的纳米复合反渗透膜的构建及其抗污染机理

For traditional polyamide thin film composite reverse osmosis membrane, there are three prominent drawbacks: the insufficient water flux, poor antifouling and antioxidative properties. In this project, the preparation of polyamide thin film nanocomposite reverse osmosis membrane with uniform nanoparticles and the antifouling mechanism will be investigated for solving the above prominent drawbacks. The strategy for obtaining the uniformly dispersed nanoparticles in the polyamide matrix is to combine the in situ preparation of nanoparticles process with the traditional preparation process of polyamide thin film composite membrane. The relationship between the character of nanoparticle and the structure of the thin film nanocomposite membrane will be ascertained by studying the effect of nanoparticles with different size and different type on the chemical structure and the microstructure of the membrane. The relationship between the character of membrane surface and the antifouling performance of the thin film nanocomposite membrane will be ascertained by investigating the surface charge, surface hydrophilicity, surface free energy and surface roughness. The membrane formation mechanism and the antifouling mechanism will be revealed by the above results. This project will be valuable for the application of the thin film nanocomposite reverse osmosis membrane in the field of wastewater advanced treatment and reuse.

针对传统的聚酰胺复合反渗透膜存在水通量不够高、抗污染性能差以及抗氧化性能低的问题，本项目提出构建纳米粒子均一分散的聚酰胺纳米复合反渗透膜并开展其抗污染机理研究。将纳米粒子的原位制备与界面聚合制备聚酰胺复合膜过程有机结合，获得无机纳米粒子在聚酰胺基体内均一分布的控制手段。剖析不同粒径、不同种类的无机纳米粒子对膜表面化学结构及微观形态结构的影响，建立纳米粒子性质与纳米复合膜结构的构效关系。考察纳米复合膜表面电荷、亲水性、表面自由能和表面粗糙度等参数对纳米复合膜抗污染性能的影响，建立纳米复合膜的表面性质与抗污染性能的内在联系。通过这些科学问题的研究和探索，阐明纳米复合膜的成膜机理和抗污染机理，为纳米复合反渗透膜在污水深度处理及回用领域的实际工程应用提供技术支撑。

针对传统的聚酰胺复合反渗透膜存在水通量不够高、抗污染性能差的问题，将界面聚合制备聚酰胺复合膜与原位改性有机结合，通过氨基功能化氧化石墨烯上的氨基/N-羟乙基吗啉上的羟基与初生态聚酰胺膜表面上未反应的酰氯基团进行化学反应，制备了高通量的聚酰胺反渗透膜；并对氧化石墨烯/N-羟乙基吗啉浓度、浸渍时间、热处理时间等关键原位改性工艺参数等进行了系统的探讨。此外，系统研究了原位改性对反渗透膜表面形态、化学组成、表面粗糙度、表面电位和亲水性等表面性质的影响机制，建立了改性膜表面性质和脱盐性能之间的内在联系，提出了氧化石墨烯/N-羟乙基吗啉原位改性聚酰胺反渗透膜的成膜机理和抗污染机理。改性膜的通量高达125.71 L/m2/h，NaCl截留率为98.6%。与陶氏BW-30膜相比，水通量提高了112%，盐截留率也略有提高。此外，通过在界面聚合有机相中添加均一分散的氟化氧化硅纳米粒子，制备了纳米粒子均一分散的氟化氧化硅-聚酰胺纳米复合反渗透膜。对界面聚合时间、热处理温度以及纳米粒子的添加量等关键成膜工艺参数等进行了系统的探讨，并研究了疏水性纳米粒子对反渗透膜表面形态、化学组成、表面粗糙度和亲疏水性等表面性质的影响机制，阐明了疏水性纳米粒子对纳米复合反渗透膜结构和性能的强化作用机理。通过这些科学问题的研究和探索，为高性能反渗透膜在污水深度处理及回用领域的实际工程应用提供技术支撑。