ABSTRACT
Nanoscale zero valent iron (nZVI) has been used to treat contaminated subsurface for almost two decades. Since the first application, development made in several key areas has deepened the knowledge of the benefits and disadvantages of nZVI-based remediation applications. This chapter aims to summarize and review the general features and the latest updates in nZVI technology. First, nZVI technology is briefly described, followed by the both common nZVI synthesis methods (chemical reduction and milling) and innovative methods (ultrasound, electrolysis, and green synthesis). It is well known that nZVI tends to aggregate in aqueous media. Therefore, nZVI colloidal stability and ways of nZVI stabilization and immobilization are summarized. Furthermore, nZVI structure, aqueous chemistry, aging due to the geochemical and biological interactions with the surrounding environment and the reactivity with common environmental contaminants are reviewed. Successful delivery of nZVI into the contaminant zone is one of the critical issues of nZVI technology; thus, the mechanisms affecting transport in porous media are identified. This review also focuses on field implementation and laboratory test that may help in optimal application of nZVI in the subsurface remediation. Finally, interaction with living microorganisms, non-groundwater remediation applications, and future challenges are summarized.
