Importance of oxidative steps in zero-valent iron reductive processes for the treatment of organic pollutants: a short review

Abstract

Zero-valent iron (ZVI) is a reductive process commonly employed in groundwater remediation; however, in this process, there is a possibility for oxidative pathways to occur, and they might be of importance for pollutant remediation. In the first part of this work, we provide information on key parameters ruling this process. In the second part, we emphasize on the importance of oxidative steps in ZVI treatment, in particular, Fenton-like process driven by hydrogen peroxide generated mainly in aerated media. Also, we describe the use of ZVI as reservoir of iron for neutral Fenton process or for persulfate activation and provide examples of the implementation of sequential reductive and oxidative processes with potential niche applications. Throughout the work, key mechanistic aspects are addressed, and examples of waste valorization to obtain ZVI-based materials and processes are given, also reporting on the role of dissolved organic matter as auxiliary.