Oxidation of organic contaminants in water by iron-induced oxygen activation: A short review

Abstract

Reduced forms of iron, such as zero-valent ion (ZVI) and ferrous ion (Fe[II]), can activate dissolved oxygen in water into reactive oxidants capable of oxidative water treatment. The corrosion of ZVI (or the oxidation of (Fe [II]) forms a hydrogen peroxide (H2O2) intermediate and the subsequent Fenton reaction generates reactive oxidants such as hydroxyl radical (• OH) and ferryl ion (Fe[IV]). However, the production of reactive oxidants is limited by multiple factors that restrict the electron transfer from iron to oxygen or that lead the reaction of H2O2 to undesired pathways. Several efforts have been made to enhance the production of reactive oxidants by iron-induced oxygen activation, such as the use of iron-chelating agents, electron-shuttles, and surface modification on ZVI. This article reviews the chemistry of oxygen activation by ZVI and Fe(II) and its application in oxidative degradation of organic contaminants. Also discussed are the issues which require further investigation to better understand the chemistry and develop practical environmental technologies.

Differential Microbicidal Effects of Bimetallic Iron–Copper Nanoparticles on Escherichia coli and MS2 Coliphage

“…Zerovalent iron and copper release ionic iron and copper species, such as Fe­(II), Cu­(I), and Cu­(II), as they are corroded by oxygen (intracellular or extracellular) and cellular components. Reactions – describe the corrosion process of zerovalent iron and copper by oxygen. , Among the ionic iron and copper species, Cu­(I) is known as a strong microbicide, and it has been suggested to be responsible for the bactericidal actions of different copper-based antimicrobial systems. ,, …”

“…Iron nanoparticles, particularly nanoparticulate zerovalent iron (nZVI or Fe-NPs), have been reported to exhibit antimicrobial properties. − Investigators found that Fe-NPs inactivate Escherichia coli and MS2 coliphage mainly by inducing oxidative damage to the cells and viral particles. − Fe-NPs and ferrous ion released from Fe-NPs generate reactive oxidants, such as hydroxyl radical ( • OH) and ferryl ion [Fe­(IV)], via the Fenton­(-like) reactions . Fe-NPs exhibited microbicidal activity superior to that of silver nanoparticles under anoxic conditions .…”

In Situ Chemical Reduction of Chlorinated Organic Compounds

“…The presence of dissolved oxygen (DO) will result in the formation of reactive oxygen species (ROS, Eqs. 6.32-34) and ferryl iron Fe(IV)O 2+ (Keenan and Sedlak 2008;Lee 2015), in order to promote oxidative processes. However, the reactive oxidant yield is generally low and does not allow to benefit from Fenton reaction for practical applications, without any modification or use of ligand (Mu et al 2017).…”

Nanomaterials: Green Synthesis for Water Applications

“…When nZVI degrades organic pollutants, the nanoparticles serve as electron donors. The two electrons are transferred to an oxygen molecule to form hydrogen peroxide, which is further reduced to a water molecule [41]. The degradation mechanism of pollutants can be summarized according the following reactions (Eqs.…”