镶嵌氧化石墨烯包覆壳聚糖（GO@CS）核壳结构纳米粒子的反渗透复合膜的可控制备及传递机理研究

Seawater desalination is one of the most siginificant approches to alleviate the water resources shortage all over the world. Reverse osmosis (RO) has become one of the most economical techniques in seawater desalination industry, and the development of new membrane materials for high performance RO membranes is one of the most critical issues to decrease the desalination cost. Graphene is well-known for its potential application in the preparation of RO membranes with high flux and high salt rejection, but the performance of the state-of-the-art graphene RO membranes can’t meet the expected demands. In this research, we propose a kind of novel core-shell (GO@CS) nanoparticles which are characterized by spherical shell nanochannel prepared by wrapping chitosan (CS) nanoparticles with graphene oxide (GO). We intend to extensively investigate the effect of preparation conditions on the performance of the proposed GO@CS nanoparticles. Further, we plan to prepare nanoparticle-doped aromatic polyamine RO membranes via interfacial polymerization method by dispersing GO@CS nanoparticles in either water phase or oil phase solution. We also have a strong willing to reveal the interrelationship between the RO membrane permeability and some parameters such as the size and the shell thickness of GO@CS nanoparticles, the extent of crosslinking, as well as the extent of oxidation of GO, and so on. Meanwhile, we intend to characterize the microstructure of GO@CS core-shell nanoparticles and their distribution in the skin layer of RO membranes by transmission electron microscope (TEM), scanning electron microscope (SEM) and X-ray diffraction (XRD) in order to reveal the relationship between structure parameters and separation performances of the RO membranes. We would further propose a structural model of GO@CS nanoparticle-doped RO composite membranes, and simultaneously, explore the mechanism of salt rejection and water transport within the spherical shell nanochannel of the core-shell (GO@CS) nanoparticles. In conclusion, this research will provide enough theoretical support for the preparation and application of GO-based high-performance RO desalination membranes.

随着水资源危机的日益加剧，海水淡化已成为解决淡水资源短缺的战略性选择，反渗透法已成为最主要的海水淡化方法之一。高通量反渗透膜的开发在膜制备领域引起了广泛的兴趣。石墨烯在高性能海水淡化膜制备方面具有很大的应用潜力，但文献报道的石墨烯膜通量低、脱盐率低。本项目拟研制氧化石墨烯包覆壳聚糖（GO@CS）的核壳结构纳米粒子，深入研究该纳米颗粒的球壳状二维纳米通道的水透过性能和脱盐性能，采用界面聚合法制备高通量和高脱盐率的GO@CS核壳结构纳米粒子镶嵌反渗透复合膜，研究纳米粒子的尺寸、GO自组装壳的厚度、GO的交联程度、GO的还原程度等对镶嵌膜渗透性能的影响，通过透射电镜、扫描电镜、X射线衍射等方法分析核壳结构纳米粒子的结构及其在膜中的镶嵌方式，揭示镶嵌膜的结构与性能间的关系，建立结构模型，阐明镶嵌膜内水分子的传递机制和离子的截留机制，为基于氧化石墨烯的高性能脱盐膜的制备及实际应用提供理论依据。

随着水资源危机的日益加剧，海水淡化成为解决淡水资源短缺的战略性选择，反渗透法是目前最主流的海水淡化方法之一。高通量反渗透膜的开发在膜制备领域引起了广泛的关注。.本项目基于氧化石墨烯在高性能海水淡化膜制备方面的应用潜力，针对现有报道的石墨烯膜存在通量低、脱盐率低等问题，通过反相乳化交联法制备了尺寸可控的壳聚糖纳米微球，采用Hummers法和超声剥离法制备了尺寸、厚度、氧化程度可控的氧化石墨烯纳米片，然后通过自组装法制备了氧化石墨烯包覆壳聚糖（GO@CS）核壳结构纳米粒子；深入研究了GO@CS的球壳状二维纳米通道的水透过性能和脱盐性能；采用界面聚合法制备了GO@CS核壳结构纳米粒子镶嵌聚酰胺反渗透膜，研究了纳米粒子的尺寸、GO自组装壳的厚度、GO的交联程度、GO的还原程度、GO@CS的添加位置及浓度等对镶嵌膜渗透性能的影响，通过透射电镜、扫描电镜、X射线衍射等分析了核壳结构纳米粒子的结构及其在反渗透膜中的镶嵌方式，建立了GO@CS镶嵌反渗透膜结构模型，揭示了GO@CS镶嵌反渗透膜的结构与性能之间的构效关系，阐明镶嵌膜内水分子的传递机制和离子的截留机制；通过界面聚合法制备了二甲基亚砜辅助GO@CS镶嵌聚酰胺反渗透膜，其纯水通量大于100L•m-2•h-1，对NaCl的脱盐率大于99%。在小型反渗透复合膜制备装置上对二甲基亚砜辅助GO@CS镶嵌聚酰胺反渗透膜进行试制，通过SEM、TEM、AFM、XRD、Zeta电位、水通量、脱盐率等表征，证明所制备的反渗透膜具有较好的结构及性能稳定性。.本研究工作为基于氧化石墨烯的高通量、高脱盐率反渗透膜的制备及实际应用提供了理论依据。