Review on Nano zerovalent Iron (nZVI): From Modification to Environmental Applications

Nanoscale zero-valent iron (nZVI), with its reductive potentials and wide availability, offers degradative remediation of environmental contaminants. Although nZVI particles were successfully used in wastewater treatment, there are still some drawbacks associated with the process and needs to be addressed. For example, magnetic attraction between nanoiron particles causes the rapid aggregation of particles. In addition, nZVI are more prone to react with dissolved oxygen and oxygen-rich compounds. Meantimes, nZVI could exert some degree of toxicity towards microbial species, and the effects of nZVI at the cellular and community levels are progressively being elucidated. To overcome these problems, nZVI particles were immobilized in or on suitable solid supports, and also to expand the effective pH range of the Fenton reaction. Therefore, refer to the new trends is very important when selecting nZVI for the treatment of various matrices. This review also identifies problems that may occurs a result of changes in the physicochemical properties of nZVI due to their modification (e.g. other metal doping, coating the surface, or deposition on the support). Toxicity studies suggest that cellmembrane disruption and oxidative stress through the generation of Fe2+ and reactive oxygen species by nZVI are the main mechanisms contributing to nZVI cytotoxicity. This review highlights the application of nano-zero valent iron in treating refractory compounds.