Fe3O4-C双壳中空纳米球的可控合成及对重金属离子的吸附研究

Magnetic nanomaterials have excellent adsorption performance for heavy metal ions, but their high surface activity and instability have seriously hampered the stability of adsorption performance. Therefore, they should be wrapped in a protective layer on their surface or modified to improve their performance. Although many scholars are actively exploring the application of magnetic nanomaterials in heavy metal adsorption, the research in chemical behavior of heavy metals in solid - liquid interface system is more focused on the macro level of thermodynamics and kinetics. The project intends to use different sizes of monodisperse SiO2 microspheres as templates, and solvothermally prepare SiO2@Fe3O4@C core-double hull structure using one-step method oxidation of ferrocene by hydrogen peroxide. Then the controllable synthesis of superparamagnetism Fe3O4-C bivalve hollow nanospheres can be realized after removed SiO2 core with strong base. The microstructure of the product and formation mechanism of the double-shell can be revealed by structural characterization and performance testing. The isotherm and dynamic adsorption process can be studied through adsorption experiments, and the adsorption effect can be determined for Pb2 +, Hg2 + and Cd2 +. Combined with IR, XPS and XAFS test results, the adsorption mechanism of Fe3O4-C bivalve hollow nanospheres for a single metal ion and competitive coexistence of a variety of heavy metal ions can be clarified from the macro and micro molecular level. This project will provide important scientific basis and practical application value for the in-depth study of magnetic nanocomposite adsorbents.

磁性纳米材料对重金属离子具有优良的吸附性能，但高的表面活性及不稳定性严重影响吸附性能稳定发挥。因此须对磁性纳米材料表面进行包裹或改性以提高性能。很多学者都在积极探索磁性纳米材料在重金属吸附中的应用，但对重金属在固–液界面体系的化学行为研究多集中在宏观热力学和动力学层面。本项目拟用过氧化氢在SiO2微球模板表面氧化二茂铁，一步法制SiO2@Fe3O4@C核-双壳结构，进而用强碱除去SiO2核，可实现超顺磁Fe3O4-C双壳中空纳米球的可控合成。通过结构表征及性能测试，揭示产物微结构及双壳层形成机制。通过吸附实验研究其吸附等温式和动力学过程，确定产物对Pb2+、Hg2+、Cd2+的吸附效果。结合IR、XPS、XAFS等测试结果，从宏观层面及微观分子水平来阐明产物对单一重金属离子的吸附机制及多种重金属离子共存的竞争吸附机理。本项目将为磁性纳米复合吸附剂的深入研究提供重要的科学依据和实际应用价值。

当今世界，随着工业生产和城市现代化的发展，环境问题日益成为人们关注的课题。水是人类赖以生存和发展的物质基础，而重金属离子对水质的污染已对人类的生存造成了极大的威胁，因此重金属污染治理问题备受人们关注。近年来，对吸附剂的研究逐渐由单一的吸附剂向新型复合吸附材料转变，新型复合吸附剂成为研究热点。于是，碳包覆的Fe3O4纳米粒子被认为是很有潜力的净化废水的有力工具，由于碳层的存在和易功能化的表面，以及对于外部磁场具有强烈的响应，它们不仅具有较高的吸附能力，也可以很方便地在废水处理后进行去除且不会造成二次污染。. 本项目研究了Fe3O4-C双壳中空纳米材料的合成以及对重金属离子的吸附。在溶剂热体系中一步法制备了超顺磁性SiO2@Fe3O4@C核-双壳结构纳米粒子；进而用强碱除去SiO2模板，形成了均一性及分散性良好，粒子的粒径大小在200nm左右的Fe3O4-C双壳中空纳米球。通过形貌结构分析及形成机理研究，揭示了产物Fe3O4-C双壳中空纳米球的微结构及双壳层形成机制。通过Fe3O4-C双壳中空纳米球对重金属离子的吸附，研究了Fe3O4-C双壳中空纳米球对重金属离子的吸附机理。.