共存Fe(II)对水合氧化铁吸附重金属离子行为的影响

项目名称： 共存Fe(II)对水合氧化铁吸附重金属离子行为的影响

项目编号： No.20877021

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 化学工业

项目作者： 刘辉

作者单位： 河北师范大学

项目金额： 33万元

中文摘要： 水合氧化铁(Fh)普遍存在于自然环境中，因有高的表面积和反应活性，在控制污染物的环境行为方面发挥着重要作用。按照文献合成的Fh多经历了由酸性过渡到中性的过程，而自然环境中Fh多在近中性条件下形成，特殊条件下也可能在偏酸性或碱性条件下形成。本课题采用三种方法合成了Fh，利用多种手段对其表征，系统研究了铅、铜、镉、锌和铬等重金属离子在单一和混合体系中在Fh/水界面上的吸附平衡性质、吸附－解吸过程以及吸附热力学和吸附动力学规律，考察了各种因素以及共存Fe(II)对Fh吸附性能的影响。结果表明：不同条件制备的Fh的微结构有显著差异，中性环境制备的Fh对各种重金属离子均表现出较大的吸附容量和较强的锁定能力。以三种Fh为催化剂，考察了其对不同偶氮染料的光催化降解过程。结果表明：中性环境制备的Fh对偶氮染料也表现出较大的吸附容量，但降解率大小则取决于污染物与Fh的结合力的强弱。本研究从一个新的角度探索了环境温度下Fh的吸附及光催化性能，为客观评价重金属污染物在环境中的浓度、滞留、迁移、转化、生物可利用性及毒性等环境行为的提供了基础数据，因而具有重要的理论及环境意义。

中文关键词： 水合氧化铁；形成条件；结构表征；吸附性能；催化活性

英文摘要： Ferrihydrite(Fh) is a common Fe(III) (hydr)oxide in soils and sediments in natural aquatic environment. Owing to its high surface area and intrinsic reactivity, ferrihydrite plays an important role in controlling environmental behavior of pollutants. Ferrihydrite in most references was prepared by the method reported by Cornell et al. Here, the formation of ferrihydrite went through a pH change from acidic to neutral. However, ferrihydrite occurs in many environments under circumneutral conditions. In this program, ferrihydrites prepared by three procedures (named Fh-1, Fh-2 and Fh-3) were used as sorbents and Pb, Cu, Zn, Cd, and Cr were selected as model pollutants. The aim is to investigate the adsorption behaviour and kenitics of those heavy metals on the interface of ferrihydrite/water, and the effect of Fe(II) coexisting with ferrihydrite as well as various factors on the adsorption capacity of ferrihydrite. The results show that there are differences in the microstructure of the three Fhs. Fh-3 has a higher adsorption capacity and a stronger ability to bind heavy metal ion even in the presence of trace Fe(II). Moreover, a system of Fh/H2O2/UV or visible light was established to investigate the adsorption and degradation of azo dyes on ferrihydrite. A great adsorption capacity was observed in Fh-3 system, while the degradation rate of azo dyes depends on their bonding ability to adsorbents. The results obtained in this program are helpful for us to evaluate the environmental behavior of heavy metal contaminants, including concentration, fate, transport, transformation, bioavailablity as well as toxicity.

英文关键词： ferrihydrite; formation condition; structural characterization; adsorption performance; catalytic activity;