层离蒙脱石和水溶性聚合物界面作用下零价铁纳米颗粒的可控制备及机理研究

Zerovalent iron nanoparticles (ZVINs) in our previous work have been hybridized with delaminated montmorillonite (Mt) particles by impregnation of Mt with ferric ions followed by chemical reduction with sodium borohydride in aqueous solution. Thus obtained nanohybrids are of great potential in the practical applications of catalysis, sorption, and decontamination. Based on these results, the objectives of this proposal are to synthesize size-, shape-, and dispersity-controllable ZVINs with delaminated Mt particles as support and with water-soluble polymers as modifier, as well as to obtain environment-friendly Mt/ZVINs nanocomposites with larger surface areas and more mesopores. This control on the properties of these nanocomposites would, to a great extent, depend on the interfacial interactions between the delaminated Mt particles and the polymer modifiers as well as on the growth processes of the ZVINs affected by the interfacial interactions in limited spaces, according to our theoretical assumptions. To achieve our objectives and to verify our assumptions, with a combination of electron microscopic and different spectral analyses, the researches of this proposal will be focused on (1) revealing the formation conditions and mechanisms of delaminated Mt in the processes of Mt/ZVINs preparation, (2) revealing the effects and mechanisms of the polymer modifiers on the stability of delaminated Mt in the processes of Mt/ZVINs preparation, and (3) revealing the effects, mechanisms, and main influencing factors of the interfacial interactions between the delaminated Mt particles and the polymer modifiers on the size, shape, and dispersity of the supported ZVINs. The research results would be essential for the controllable synthesis of nanosized mineral composites and elucidation of the related mechanisms, as well as essential for the cross-disciplinary integration of nanotechnology and clay mineralogy, and for the development of environmental mineralogy.

申请人前期利用蒙脱石在水溶液中发生层离并与铁离子还原产物纳米铁作用的特性，制备了蒙脱石/零价铁纳米复合物，这种复合物性能优异，在催化、吸附及环境修复等领域应用前景较好。本项目拟引入水溶性聚合物作修饰剂，进一步研究这种复合物的可控制备方法和微观机理。拟在硼氢化钠液相还原体系中，借助水溶性聚合物和层离蒙脱石颗粒之间的界面作用及其对局域化学反应的控制作用，调控纳米铁尺寸、形状、分散性，发展制备比表面积较大、介孔发达、性能可控的蒙脱石/零价铁纳米复合物的新方法。借助电镜和多种谱学技术手段，着重研究制备过程中蒙脱石层离结构的形成条件及机制，揭示水溶性聚合物对层离蒙脱石稳定性的影响规律，进而阐明层离蒙脱石和水溶性聚合物控制纳米铁性能的界面作用过程、影响因素及作用机制。研究成果对定向设计合成纳米复合矿物材料，明确复合材料性能调控界面作用过程，促进纳米科学与矿物学交叉发展，深化环境矿物学研究具有重要意义。

零价铁纳米颗粒以其卓越的磁性能及巨大的应用潜力备受瞩目，硼氢化钠化学液相还原铁盐是对其进行制备的一种简便、经济、高效方法。但是，采用这种方法制备零价铁纳米颗粒面临着制备过程受众多因素影响难于控制、零价铁纳米颗粒容易氧化和团聚等困难。实际应用及一般研究中显然希望利用硼氢化钠化学液相还原制备零价铁纳米颗粒更简便、更能提高反应重现性、更能减少杂质含量、更能使铁纳米颗粒抗氧化性能改善。申请人前期利用蒙脱石在水溶液中发生层离并与铁离子还原产物纳米铁作用的特性，制备了蒙脱石/零价铁纳米复合物，这种复合物性能优异，在催化、吸附及环境修复等领域应用前景较好。在此基础上，本项目引入水溶性聚合物作修饰剂，进一步研究了这种复合物的可控制备方法和微观机理。在硼氢化钠液相还原体系中，借助水溶性聚合物和层离蒙脱石颗粒之间的界面作用及其对局域化学反应的控制作用，调控了纳米铁尺寸及分散性，发展了制备介孔发达、性能可控的蒙脱石/零价铁/水溶性聚合物纳米复合材料的新方法。借助电镜和多种谱学技术手段，着重研究了制备过程中蒙脱石层离结构的形成条件及机制，揭示了水溶性聚合物对层离蒙脱石稳定性的影响规律，进而阐述了层离蒙脱石和水溶性聚合物控制纳米铁性能的界面作用过程、影响因素及作用机制。研究成果对定向设计合成纳米复合矿物材料，明确复合材料性能调控界面作用过程，促进纳米科学与矿物学交叉发展，深化环境矿物学研究具有重要意义。