三明治结构磁性介孔印迹材料的设计、合成及其分离稀土的研究

It is a high efficient and green technology to recover and separate of rare earth(III) ions from complicated dilute aqueous solution by a new kind of solid-liquid adsorption process, which combined the molecular imprinting technology and magnetic assistant chemical separation (MACS). Rare earths(III) ion-imprinting superparamagnetic microspheres with an Fe3O4@SiO2 core and a perpendicularly aligned mesoporous SiO2 shell will be designed and prepared by first. The adsorption behavior and mechanism of the synthesized polymer towards the whole rare earths(III) will be examined. The possible synergism and steric hindrance effect result from the spatial structure and the functional sites of the imprinted polymer will be investigated through the adsorption experiments and instrumental characterization. The determinant factors of rare earths(III) adsorption performance will be analyzed based on the effects of particle size, porous structure, molecular geometry and categories of ligands on adsorption. The successful realization of this project will provide a technological and theoretical prototype for the design and preparation of magnetic carriers and ion-imprinting polymers, and promote the development of efficient and environment-friendly metallurgical processes of the rare earth ions recovery and separation.

低浓度复杂体系中稀土的分离回收研究具有重要的价值。本项目拟设计、制备以超顺磁性核壳结构Fe3O4@SiO2为核，以稀土离子印迹并具有规则介孔结构SiO2为壳的三明治结构磁性介孔印迹材料 (IIP-Fe3O4@nSiO2@mSiO2)，利用磁力辅助实现纳米稀土吸附剂与吸附后溶液的高效分离。研究吸附剂对稀土的吸附分离性能，考察稀土吸附分离机理以及全稀土吸附规律。通过吸附实验以及吸附剂微观结构的表征，探讨稀土离子吸附配位过程中，印迹聚合物的空间结构和功能团结合位点可能存在的协同效应和空间效应；通过比较分析不同载体的粒径、孔结构、配体分子的结构、种类的差异与稀土离子吸附性能之间的相关性，解析稀土吸附性能的决定因素，为新型稀土吸附剂的设计、合成奠定基础。

加强对低浓度稀土料液或废水等复杂体系中稀土的回收与分离技术的研究具有重要的科学意义和工业价值。本项目采用高温热分解合成了超顺磁性Fe3O4纳米颗粒，通过TEOS的两步溶胶凝胶法和离子印迹法，合成Nd(III)印迹的三明治结构的磁性硅基磁颗粒，用于从溶液中选择性富集和分离稀土离子。Nd(III)印迹三明治结构的硅基磁颗粒对稀土Nd(III)有着优良的吸附性能，Nd(III)可以在30 min内实现完全吸附平衡，25℃下Nd(III)的饱和吸附容量为0.210 mmol/g。0.2 mol/L的盐酸可以实现负载Nd(III)的完全解吸，吸附剂可以循环再生。且超顺磁性的吸附剂易于磁力辅助液固分离和超声再分散。Nd(III)印迹能显著提高吸附剂对Nd(III)的分离选择性，Pr(III)/Nd(III)的分离系数可以达到1.62，能与商业萃取剂对稀土的分离性能相媲美。Nd(III)印迹三明治结构的硅基磁颗粒对稀土Nd(III)吸附主要依靠Nd(III)与吸附剂上的-COOH官能团中H+的阳离子交换作用。本项目的研究为性能良好的新型磁性吸附剂的制备以及金属离子吸附分离的应用工艺研究提供了基础数据，理论依据以及进一步研究的方向。