基于同步辐射原位QXAFS方法研究纳米Fe0去除饮用水中As(III)的反应机制

In many of the arsenic removal method, adsorption method was widely used around the world for its simple and effective. Especially nano zero-valent iron (Fe0) due to low cost, high adsorption and does not produce secondary pollution, was widely concerned at present. Represented by Ti (SO4)2 coagulation of Fe0 nanomaterials, which has a larger binding energies. Because the flocs and As(III) generates the angle of shared bidentate dinuclear complexes, so may get bigger As(III) adsorption capacity. Many researchers interest were attracted. However, the structure and the adsorption mechanism between Fe0 nanomaterials and As(III) is not yet clear, thereby limiting the development of the higher performance materials. This project using the in-situ QXAFS method, from the perspective of microstructure, investigates the micro mechanism of the reaction process between Fe0 materials and As(III) under real adsorption system. Through the geometric structure and the electronic structure analysis of Fe ions and As(III), explore the adsorption ability of Fe0 materials associated with the micro structure. By improving the preparation technology, building the correlation between local structure and adsorption capacity in the process of adsorption for nanomaterials. As the design and synthesis of nano Fe0 materials with higher arsenic removal ability provide theory basis.

在众多的除砷方法中，吸附法因其简单有效而被世界各国广泛应用。尤其纳米零价铁（Fe0）材料因价格低廉、吸附量高、不产生二次污染，目前受到广泛关注。以Ti(SO4)2混凝为代表的纳米Fe0材料，因其絮体与As(III)之间生成了角共享的双齿双核内层配合物，具有较大的结合能，因此获得较大的As(III)吸附能力，更引起众多研究者的兴趣。然而对于纳米Fe0材料吸附As(III)的结构研究和吸附机理之间的关联尚不清晰，从而限制了更高性能材料的开发。本项目利用原位QXAFS方法，从微观结构的角度探讨真实体系下纳米Fe0材料吸附As(III)反应过程的微观机理，通过Fe离子与As(III)的几何结构与电子结构分析，探讨纳米Fe0材料的吸附能力与体系微观结构的关联，通过改善制备工艺，建立材料吸附过程中的局域结构与吸附能力之间的关联，为设计合成具有更高除砷能力的纳米Fe0材料提供理论依据。

本项目结合在吸收谱方法、理论计算以及Fe0材料制备和表征等方面的研究经验，利用永磁铁提供的弱磁场促进零价铁在水中的腐蚀，采用同步辐射XAFS方法，结合XRD、SEM、TEM、吸附量分析等常规表征手段，对Fe0材料吸附过程中金属元素的电子结构和配位结构开展研究，通过分析溶液中Fe2+的产生以及As(III)/As(V)在溶液中的演变，考察弱磁场条件下，Fe0去除As(III) /As(V)效果的影响。设计了一套用于液体分析的原位反应实验装置，研究Fe0材料的As(III)吸附过程，发展Fe0材料除砷的XAFS原位研究方法，开展动态反应条件下饮用水中As(III)去除的机理研究。