孔壁包埋磁性纳米颗粒型介孔材料的制备及固相萃取研究

In this project, we aim to encapsulate magnetic nanoparticles (MNPs) into the pore wall of mesoporous silica and mesoporous carbon to get ordered mesoporous materials, and attempt to develop a novel solid-phase extraction (SPE) method based on the prepared materials. To prepare magnetic mesoporous materials, phenolic resin and tetraethylorthosilicate (TEOS) are used as carbon and silica source, respectively, and PEO-PPO-PEO triblock copolymers as template agent. In mixture solution, triblock copolymers form liquid crystal template, and ultrafine MNPs and carbon or silica sols will self-assemble into hydrophilic chains, then sols are aged into dried gels. The dried gels are calcined to remove template to get ordered mesoporous meterials with MNPs embedded in pore wall. The incorporation of MNPs into pore wall of mesoporous materials will not only endow the materials superparamagnetism, but also maintain their ordered mesoporous structure. This novel structure keeps the strong adsorptive capacity and rapid adsorption/desorption character of mesoporous material. Moreover, MNPs can be protected by the silica shell from lossing magnetic property due to fall off, oxidation, or acid digestion. Several typical pollutants are selected as target compounds to investgate their adsorption/desorption behaviour on prepared magnetic mesoporous materials. The effects of extraction conditions on recoveries of target compounds are tested, and under optimized conditions, a novel magnetic SPE method are developed for preconcentration of target compounds from environmental samples containing complex matrix. This project, combining nanotechnology, self-assemble technique, magnetic separation technology and SPE method, is a original research with great academic value and good application prospect.

本项目提出将磁性纳米颗粒包埋于介孔硅和介孔碳的孔壁，制备有序磁性介孔材料，以其为吸附剂建立新型磁性固相萃取方法。分别以正硅酸乙酯和酚醛树脂作为硅源和碳源，聚氧烯烃嵌段聚合物为模板剂，将超细磁性纳米颗粒自组装到液晶模板的亲水段，陈化使溶胶交联聚合为干凝胶，焙烧除去模板，得到的材料磁性纳米颗粒包埋于介孔孔壁，既赋予材料超顺磁性，又不会破坏其有序介孔结构。这种新型结构有利于保持介孔材料强的吸附性能、快速吸附/脱附的动力学特点，同时包埋于孔壁的磁性纳米颗粒能够得到有效地保护，防止其由于脱落、氧化、酸消解等而失去磁性能。选用典型的环境污染物为目标物，研究其在磁性介孔材料上的吸附/脱附性能，考察萃取条件对回收率的影响，建立新型固相萃取方法，并用于从具有复杂基体的环境样品中萃取分析目标物。项目将纳米、自组装、磁分离和固相萃取技术结合为一体，是一项具有重要学术价值和应用前景的原创性研究。

介孔材料具有有序的介孔结构，较大的比表面积和孔体积等性能，在众多领域的应用得到了研究。在介孔材料中进入磁性纳米颗粒可以实现介孔材料的磁操控，近年来磁性介孔材料的合成和应用引起了广泛关注，也取得了较大的进展，但仍然存在一些问题有待进一步探索。本课题以磁性介孔材料的制备与表征、表面修饰和材料改性以及用于水体中微污染物的富集和去除为主要研究内容，设计合成了多种磁性介孔材料，并研究了其吸附分离性能。制备了磁性介孔硅材料，并用巯基进行修饰，该材料可以用于水体中微量汞的富集分析和去除。将磁性纳米颗粒镶嵌于介孔聚合多巴胺聚合物中得到的复合材料，能够同时吸附重金属，染料等多种微污染物。制备的磁性多孔生物质活性炭可以有效的吸附和催化降解有机染料污染物。以介孔硅SBA-15为硬模板，以聚合多巴胺为碳源，Fe3+为铁源制备的有序磁性介孔碳对水体中的有机污染物显示出了良好的吸附性能。本研究成功的合成了几种对水体中污染物具有良好吸附性能的磁性介孔材料，为磁性复合材料的制备和在环境领域的应用开拓了新的思路，取得了一些原创性的科研成果，具有十分重要的学术意义和应用价值。