面向青海盐湖卤水锂提取过程强化的高性能中空纤维正渗透膜材料的设计研究

项目以盐湖卤水锂提取过程强化和核心材料为目标，针对现有的吸附-反渗透/蒸发-沉淀提锂技术在浓缩效率和核心材料方面的不足，提出以高浓老卤和无机盐驱动的、低能耗的正渗透浓缩过程。拟通过设计高通量、低离子反向扩散的中空纤维正渗透膜材料，强化锂提取过程效率，降低能耗，并掌握核心材料制备技术。设计关键是解决亲水支撑结构的结构参数、传质系数以及通量与分离皮层对单价/二价离子截留率的矛盾。项目研究以低结构参数、亲水中空纤维支撑膜为基础，提出采用涂敷磺化聚醚醚酮、层层自组装聚电解质涂层作为中间层，通过支撑结构和界面聚合分离皮层之间的物理、化学结合、分离皮层与中间层之间相互贯通，获得高截留率和高稳定性的正渗透膜材料。项目研究将通过与青海高校和企业合作，完成从实验室到中试研究，为青海盐湖卤水提锂的过程强化提供低能耗技术，并为下一代适合于高盐卤水浓缩的高性能正渗透膜材料制备提供新的科学思路和关键技术。

Current practice on adsorption-reverse osmosis/evaporation-chemical precipitation has been successfully demonstrated for lithium recovery from Qianghai salt-lake brine. As an environmentally friendly technology, the concentration step after adsorption-desorption using reverse osmosis/evaporation is of low efficiency and energy intensive. This proposal aims to intensify the concentration process via forward osmosis utilizing abundant discharged brine concentrate and inorganic salts on site. We target at a new generation high flux, low reverse salt diffusion hollow fiber forward osmosis membrane to establish independent intellectual property rights. We design a strongly hydrophilic substrate with a low structure parameter to reduce the mass transfer resistance and increase the flux of forward osmosis membrane. To prevent the delamination of active interfacial polymerization layer from hydrophilic substrate, an interlayer anchoring into the substrate porous structure is applied by dip-coating sulfonated poly(ether ether sulfone) and layer-by-layer polyelectrolyte. Understanding the interaction at the interface between the substrate and the interlayer, the interlayer and the active separation layer is expected to result in forward osmosis membranes with a stable, highly selective composite layer. Via collaboration with scientists from academia and industry in Qinghai Province, we will transform the results from the bench to pilot. The success of this project will provide new materials for the process intensification of the lithium recovery from salt-lake brine and novel concept/key technologies for development of next generation forward osmosis membranes for high salinity streams.