基于高铁酸盐的水污染控制技术研究进展

Advances in contaminants abatement by ferrate(Ⅵ)

高铁酸盐(FeO4^2-, Fe(Ⅵ))是一种同时具有氧化、吸附、絮凝、杀菌、消毒等多种功能的绿色水处理剂,因独特的环境友好特性而受到人们越来越多的关注.本文主要介绍了Fe(Ⅵ)的氧化特性及机理,综述了近年来基于Fe(Ⅵ)的水处理技术研究进展,包括Fe(Ⅵ)氧化新兴有机污染物及强化方面的研究、Fe(Ⅵ)杀菌消毒作用及其氧化过程中消毒副产物生成情况、Fe(Ⅵ)氧化和自分解产生的新生态铁氧化物的特性及其去除重(类)金属的机理,并对未来的研究方向和发展趋势进行了展望.

Ferrate(Ⅵ)(Fe^ⅥO4^2-, Fe(Ⅵ)) has received increasing attention as a potential water treatment chemical since it possesses oxidation, disinfection, and coagulation properties, which can be used in simultaneously remediating organic contaminants(e.g., endocrine disruptors and pharmaceuticals), inactivating microorganisms(e.g., Escherichia coli and bacteriophage MS2), and removing toxic metals(e.g., Cu(Ⅱ) and As(Ⅲ)) in water.This paper introduces the properties of Fe(Ⅵ) and its oxidation mechanisms, then reviews the research on Fe(Ⅵ)-based water treatment technologies in recent years. The benefits of using Fe(Ⅵ) as an oxidizing agent are that it produces an environmentally benign byproduct(Fe(Ⅲ)) while exhibiting high efficiency in abating pollutants in water, although Fe(Ⅵ)oxidation efficiency is limited to its stability and selectivity. The recent research results on the degradation of emerging organic contaminants by enhanced Fe(Ⅵ) oxidation technologies are presented. The induction of Fe(V) and Fe(IV) species generation in organic contaminants oxidation by Fe(Ⅵ) is the most effective method that may contribute to enhanced oxidation of organic contaminants that are less reactive with Fe(Ⅵ). Because Fe(V) and Fe(IV) have their higher oxidation reactivity than Fe(Ⅵ), and the rate constants of the reactions of Fe(IV) and Fe(V) with compounds are 2–4 orders of magnitude higher than that of Fe(Ⅵ) with compounds. It is generally accepted that no harmful byproducts such as halogenated organics and bromate would be formed during Fe(Ⅵ) oxidation. However, some recent studies have shown that disinfection by-products(DBPs) might be generated during Fe(Ⅵ) oxidation in the presence of Br–or I–. Under environmentally relevant conditions, the formation of bromate and DBPs would not be a problem for Fe(Ⅵ) application as their concentration levels are quite low. Meanwhile, the characteristics of newly formed iron(Ⅲ) oxides/hydroxide during Fe(Ⅵ) oxidation and self-decomposition, and the mechanisms for metals removal by newly formed iron(Ⅲ) oxides/hydroxide are summarized in this paper. Besides Fe(Ⅵ) oxidation, adsorption of organic pollutants and metals with Fe(Ⅵ)resultant nanoparticles could also be an effective method for water treatment and environmental remediation.Finally, the current knowledge gaps and future research needs are proposed. The economic synthesis method for ferrate remains a major challenge. The mechanism of the oxidation of organic pollutants by Fe(Ⅵ), especially the involvement of Fe(V) and Fe(IV), remains to be further clarified. The oxidation performance of Fe(Ⅵ) should be improved by greener and more efficient activation means. The oxidation and adsorption/coagulation synergetic effect of Fe(Ⅵ) should also be explored to promote the application of Fe(Ⅵ) in water pollution control. We believe that this review could inspire scientists, inventors, researchers, and engineers in this field.