纳米或亚微米磁性介孔碳材料研究及其在环境分析中的应用

This project focuses on the synthesis of nano-meter or submicro-meter scaled magnetic mesoporous carbon adsorbents and their application in the analysis of trace organic pollutants in large volume of environmental water samples with complex matrix. First, iron oxide magnetic nanoparticles (NPs) with appropriate size will be prepared through coprecipitation or microemulsion method. Next, the as-prepared iron oxide magnetic NPs, which are used as core, will be coated with a natural or synthetic polymer shell through a directly hydrothermal method with surfactant as soft template, or mesoporous silica or Al-Zn layered double hydroxides as hard template. Finally, the nano-meter or submicro-meter scaled magnetic mesoporous carbon adsorbents can be obtained by carbonization of the mesoporous polymer shell after removal of the soft or hard template. The extraction performance of the prepared magnetic mesoporous carbon adsorbents to organic pollutants will be investigated and an efficient magnetic solid-phase extraction (SPE) method will be established to achieve the sensitive and rapid analysis of trace pollutants in complex environmental water samples in conjunction with various chromatography-mass spectrometry detection technologies. In this project, novel adsorbent materials can be prepared through creative combination of nano-meter or submicro-meter mesoporous material, new type carbon material, magnetic material and SPE technology. The adsorbents possess large surface area, high extraction performance and concentration factor and can be isolated from water solution conveniently after adsorption due to the superparamagnetic property. Furthermore, size exclusion to the macromolecules of natural organic matters can be obtained by regulating the pore size, polarity and the degree of graphitization of the mesoporous carbon shell.

项目旨在制备纳米或亚微米磁性介孔碳材料吸附剂，探索其在大体积复杂基体环境水样中微量有机污染物分析中的应用。用沉淀法或微乳液法合成合适粒径的纳米磁性氧化铁粒子，以其为核心分别采用软模板、介孔硅胶硬模板、层状铝锌双金属氢氧化物硬模板、天然/合成聚合物直接水热聚合-高温碳化等方法制备纳米或亚微米磁性介孔碳材料吸附剂；考察该吸附剂对有机污染物的萃取性能，建立环境水样高效固相萃取方法，与各种色谱-质谱检测技术联用，实现对复杂基体环境水样中微量污染物的高效、灵敏、快速分析。项目创造性地将纳米/介孔材料、新型碳材料、磁性材料和固相萃取等技术结合为一体，制得全新的吸附富集材料，它们既具有很大的比表面积、强萃取能力、高富集倍数和快的萃取速度，可方便地进行萃取操作和磁性固-液分离，还可根据碳材料的介孔孔径、极性和石墨化程度等赋予其针对天然有机质等大分子的体积排阻功能。

按照项目研究计划，制备了几类核壳式或包埋式纳米/亚微米磁性介孔/多孔碳材料吸附剂和催化剂。以廉价、环境友好、容易制备的多孔磁性CaCO3晶体和双金属氧化物包覆的Fe3O4为模板，以多巴胺为碳源，制备了介孔磁性碳材料，该类材料可以快速、高效吸附去除环境水样中的三氯酚等污染物。以铜的有机金属框架为铜源前驱物和模板，酚醛树脂为碳源，合成了负载Cu/Cu2O纳米颗粒的多孔碳材料，以其为催化剂，可以高效催化硝基酚向苯胺的转化。研制了一类新型纳米材料——具有铃铛型结构的磁性介孔碳包覆的类Fenton催化剂和负载纳米金的催化剂，该类材料由SiO2或磁性Fe3O4核心、Fe3O4/C双层介孔壳及二者围绕的空腔三部分组成，具有高比表面积和多活性/吸附位点。该类催化剂所含有的空腔结构具有限域效应，在空腔内H2O2或KBH4与Fe3O4、纳米金颗粒等催化剂表面接触，产生高浓度活性物质，从而引起氯酚、硝基苯等有机污染物的高效降解。制备了C18功能化的磁性介孔碳包覆的硅胶固相萃取剂，该萃取剂可以高效富集环境水样中痕量多环芳烃污染物。制备了一种具有中空结构的金属有机框架包覆的Co3O4复合催化剂，与铃铛型催化剂相似，该催化剂的空腔结构同样具有限域效应，可以高效催化氯酚类污染物的矿化降解。这些研究成果发表在J. Mater. Chem. A、Chem. Commun.、Anal. Chem.、Environ. Sci. Technol.、ACS Appl. Mater. Interfaces、Appl. Catal. B-Environ.等国际知名期刊上，申请国家发明专利两项。