识别位点“多维空间”分布多级孔印迹整体柱的可控构筑及其选择性提锂行为与机理研究

To establish a new method for the selective extraction of lithium from the salt lake brine is of great economic value and strategic significance. This project intends to controllably fabricate hierarchical porous ion imprinted monolithic column based on recognition sites with multidimensional spatial distribution, aiming at selective separation and purification of lithium ions from the salt lake brine with high magnesium/lithium ratio. There are three characteristics of salt lake brine in our country, such as 1) viscous nature with high density, large water consumption in the lithium recovery process, 2) high magnesium/lithium ratio and low relative concentration of lithium ions, 3) similar chemical properties of magnesium and lithium ions, but possesses large difference in ionic diameter. Thus, this work is proposed to design and synthesize four kinds of functional monomers from crown ethers and their derivatives, and to graft lithium ion imprinted polymer to the guest molecule 1-adamantanol. By Pickering high internal phase emulsions template and hyper-crosslinking process, hierarchical porous ion imprinted monolithic columns modified with host molecule β-cyclodextrin are prepared. Via supramolecular interface assembly, hierarchical porous ion imprinted monolithic columns based on recognition sites with multidimensional spatial distribution are fabricated. By measuring the selective adsorption ability of lithium ions, the binding equilibrium, kinetics and thermodynamic performances are investigated. The recognition ability and mechanism are considered, and the corresponding separation and mass transfer model are established. Via optimization the separation process, a new method is established for the selective separation and purification of lithium ions from the salt lake brine with high magnesium/lithium ratio in China, and anhydrous lithium chloride products with high yield and purity are obtained.

建立高镁锂比盐湖卤水中选择性提锂新方法具有极其重要的经济价值和战略意义。本课题拟可控构筑识别位点“多维空间”分布多级孔印迹整体柱，并用于选择性分离纯化高镁锂比盐湖卤水中的锂离子。针对我国盐湖卤水①粘稠、密度大，提锂过程水量多②镁锂比高，锂离子浓度相对低③镁锂离子化学性质相似，离子直径差异性大等三大特点，本研究拟设计合成四种冠醚及其衍生物单体作为功能单体，在客体分子1-金刚烷醇端基接枝锂离子印迹聚合物；采用Pickering高内相乳液模板和后交联过程，获得主体分子β-环糊精修饰的多级孔整体柱基质；采用超分子界面组装方式，制备识别位点“多维空间”分布的多级孔印迹整体柱；探索多级孔印迹整体柱选择性分离锂离子过程中的平衡、动力学和热力学行为，研究识别能力与机制，建立相应的分离与传质模型；优化分离过程，建立适用于选择性分离纯化高镁锂比盐湖卤水中锂离子的新方法，获得高得率和纯度的无水氯化锂产品。

从高镁锂比盐湖卤水中选择性提锂具有极其重要的经济价值和战略意义。本课题首先按照原计划合成锂离子印迹聚合物功能单体；然后可控构筑识别位点“多维空间”分布的多级孔印迹整体柱，并利用多种测试表征方法对材料的结构、形貌、化学组成等理化性质进行了分析，揭示了材料的构效关系。紧接着利用合成好的多孔聚合物锂离子吸附剂选择性吸附分离锂离子，并对吸附行为、机理和模型进行研究，建立选择性分离纯化高镁锂比盐湖卤水中锂离子的新方法。其中吸附剂对锂离子具有较快的吸附速率，能在80 min左右达到吸附平衡；而且吸附剂对锂离子拥有较高的选择性，能够很好的抵抗盐湖中共存离子（如Ca2+、K+、Mg2+和Na+等）的干扰。除此之外，我们还在原有计划要点基础上，增加了三个方面的工作，拓展了研究广度、深度和应用范围。尝试采用磺酸基阴离子作为锂离子识别位点，用于识别与捕获锂离子，增加吸附剂的吸附容量，最大吸附容量可达56.458 mg/g；尝试构建了单乳液和双乳液模板体系，从中积累乳液液滴尺寸、稳定粒子接触角、内相体积比与多级孔吸附材料结构的关系，为探讨Pickering HIPEs模板制备多级孔印迹吸附剂机理提供了宝贵的经验；尝试采用纤维素纳米晶作为硬模版和十六烷基三甲基溴化铵为软模版制备多级孔硅用于锂离子提取，增强材料的传质速率。吸附剂对锂离子具有较快的吸附速率，能在100 min左右达到吸附平衡。负责人及课题组成员严格遵守《国家自然科学基金条例》规定并受益于本项目的资助，项目组紧密围绕项目研究内容开展了一系列富有成效的研究工作，已累计在Journal of Materials Chemistry A、Small、Biosensors and Bioelectronics、Chemical Engineering Journal和Journal of Cleaner Production等国际知名期刊上发表SCI论文19篇（其中标注基金号16篇）。其中一区论文13篇，影响因子大于8的12篇；累计申请国家发明专利6件；项目研究中共独立培养了博士生1名、硕士生1名；联合培养了博士生2名、硕士生2名；另有2名博士生和5名硕士研究生在读。