二维Ti3C2Tx层状膜的阳离子插层改性及对Mg2+/Li+分离性能与机制研究

我国西部地区的盐湖卤水中含有丰富的锂资源，开发适用于我国高镁锂比盐湖卤水的Mg2+/Li+分离技术,具有重要的研究价值和战略意义。本项目拟采用刻蚀技术制备单层Ti3C2Tx纳米片，利用喷涂技术进行纳米片堆叠，构筑结构完整的大面积Ti3C2Tx层状薄膜。通过不同阳离子对薄膜进行插层改性，实现膜层间距的精确调控，制备具有不同层间距的Ti3C2Tx薄膜。采用原子力显微镜联合耗散型石英晶体微天平技术，实现对阳离子插层过程中，薄膜层间微观作用力及膜结构变化的实时测量，探明离子插层Ti3C2Tx薄膜的机理。通过研究尺寸限域效应与电荷效应对分离试验过程中Mg2+、Li+的跨膜扩散性能的影响，揭示Ti3C2Tx薄膜的选择性传质机理，获得可实现Mg2+高效截留而Li+快速通过的目标膜结构与分离条件。本项目为二维Ti3C2Tx薄膜在盐湖卤水镁锂分离技术的应用及特定离子筛分功能薄膜的开发提供理论参考与支持。

There are large amount of lithium resources reserved in the salt lake brin in China, the tecnology of extractting lithium from brine with high Mg/Li ratio efficiently is of strategic and researchful significance. In this project, the selectively etching method will be chosen to prepare for the Ti3C2Tx nanosheets, the nanosheets will be spray and stacked onto the substrate surface to form the two-dimensional lamellar membrane. The lamellar membrane will be treated by the intercalation of different cation to accurately control the spacing distance between nanosheets. Atomic force microscopy (AFM) will be used in conjunction with quartz crystal microbalance with dissipation (QCM-D) to establish the test platform to observe the changes of and membrane structure and interaction forces between Ti3C2Tx nanosheets in in real time, the mechanism of cation intercalation into the Ti3C2Tx membrane will be researched and a series of Ti3C2Tx membrane with different spacing will be prepared. The size confinement effect and charge effect during the cation permeation will be studied to explore selective transport mechanism and properties, the desired membrane structure will be obtained which could exclude Mg2+ effectively with an ultrafast Li+ permeation property. This project herein provides the guidance in application of two-dimensional lamellar Ti3C2Tx membrane in Li+/Mg2+ separation in brine industry and development of the Ti3C2Tx membrane for specific cation sieving.