亚10纳米Fe(III)氧化物复合材料的制备及其高效除砷特性研究

Iron oxide nanoparticles (NPs) are very promising for decontamination of water from arsenic (As) via ligand-exchange reactions. Accompanying with decreasing NPs size below 10 nm, their decontamination reactivity could be enhanced greatly. By dispersing inside polymer matrix, the defects of NPs, such as tendency of aggregation and difficult operation, could be partially or even completely remedied without compromising their high reactivity. However, polymer-supported NPs are commonly with size from dozens of nanometers to even >100 nm arising from the wide pore size distribution of the hosts. In this project, we intend to prepare millimeter-scale mesoporous polystyrene (MesoPS) through flash-freezing method to assemble iron oxide NPs. By varying the pore size of MesoPS from 5 to 30 nm, we will investigate the effect of host pore size on growth of the confined iron oxide NPs, and thereby realizing the preparation of polymer-supported sub-10 nm iron oxides. We will focus on surface chemistry of the confined NPs and their removal efficiencies toward As. Moreover, the mechanism of As(III)/(V) adsorption onto iron oxide NPs, the effect of solution chemistry on As removal, and regeneration of the newly developed nanocomposites will be studied. We anticipate that this work could stimulate more studies towards the rational design of highly efficient environmental nanocomposites.

Fe(III)氧化物纳米颗粒（NPs）可通过配体交换实现对砷（As）的选择性吸附，当其尺寸降低到亚10 nm常表现出显著的表面效应，并大幅提升材料的深度净污性能。将NPs分散到聚合物中可有效克服其易团聚、操作困难等不足。然而，受常用聚合物载体宽孔分布的影响，制备亚10 nm Fe(III)氧化物复合材料仍面临挑战。本项目拟基于“闪速冷冻法”制备介孔聚合物，探讨载体孔结构（5-30 nm）对NPs生长过程与粒径的影响规律，开发并优化亚10 nm Fe(III)氧化物复合材料的制备方法；深入研究限域条件下亚10 nm Fe(III)氧化物形貌、晶体结构及表面化学特性的演变规律，系统评价所制复合材料的除As性能，阐明新材料吸附除As过程的表面效应；此外，还将探究溶液化学性质对新材料除As性能的影响与新材料的再生方法。本项目有望为高性能环境纳米复合材料的研制及应用提供理论与技术参考。

目前，水中砷的深度净化仍面临挑战。纳米Fe(III)氧化物可通过形成内圈配合物实现对砷的选择性去除而备受关注。为了克服纳米颗粒的实际应用瓶颈，通常需要将其负载至大颗粒载体中。受载体孔结构难以精确调控影响，目前仍难以获得高活性的亚10纳米复合材料。项目通过闪速冷冻法，制得了系列聚苯乙烯基亚10纳米Fe(III)氧化物，阐明了其表面理化特性演变规律，并揭示了其深度除砷的限域特性。此外，项目还研发了功能耦合型抗天然有机质、抗硅酸盐污染复合纳米材料。围绕上述内容，项目发表了SCI论文10篇，获授权中国/美国发明专利各1项。本项目有望为高性能环境纳米复合材料的研制及应用提供理论与技术参考。