Iron-based materials used in water treatment and groundwater remediation—especially micro- and nano-sized zerovalent iron (nZVI)—can be more effective when modified with lower-valent forms of sulfur (i.e., “sulfidated”). This study overviews current studies that apply controlled sulfidation using a variety of processes and under a range of operational conditions for various contaminant removal processes. Material characterization shows that varying sulfidation protocols (e.g., concerted or sequential) and key operational variables (e.g., S/Fe ratio and sulfidation duration) result in materials with structures and morphologies ranging from core-shell to multiphase. Two examples will then be given to illustrate the diverse effects of processes and operational variables on contaminant removal kinetics and capacity. Insights are derived from extensively established literature on sulfur induced corrosion by showing strong analogy between how sulfur affects corrosion and how sulfidation influences the rates of contaminant transformation. The results demonstrate that the broad spectrum of beneficial effects of sulfidation on contaminant removal can be ultimately explained by the corrosion processes, which has not been fully appreciated by current research. This review highlights this fundamental underlying principle, which helps to identify key data gaps for improving and optimizing sulfidation approach for groundwater remediation and water treatment in future studies.

Sulfidation of iron-based materials for contaminant removal: The diverse effects of processes and operational variables

255th National Meeting (2018)

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