Iron-based materials used in water treatment and groundwater remediation—especially micro- and nanosized zerovalent iron (nZVI)—can be more effective when modified with lower-valent forms of sulfur (i.e., “sulfidated”). Controlled sulfidation for this purpose (using sulfide, dithionite, etc.) is the main topic of this review, but insights are derived by comparison with related and comparatively well-characterized processes such as corrosion of iron in sulfidic waters and abiotic natural attenuation by iron sulfide minerals. 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. A meta-analysis of available kinetic data for dechlorination under anoxic conditions, shows that sulfidation usually increases dechlorination rates, and simultaneously hydrogen production is suppressed. Therefore, sulfidation...

Sulfidation of Iron-Based Materials: A Review of Processes and Implications for Water Treatment and Remediation.

Arsenic in the Environment: A Global Perspective

The adsorption of As(V) on alumina, hematite, kaolin and quartz has been measured as a function of pH (2 to 10), and As concentrations (10−4 to 10 −8 M; in the alumina and kaolin systems only). The effects of sulfate (0 to 80 mg L−1) and fulvic acid (0 to 25 mg L−1) were studied. The charge of the solid surface and the As speciation in solution (determined by pH) were the most important chemical parameters affecting the sorption behavior. At pH below PZC of the solid, there was a qualitative correlation between the adsorption and the anion exchange capacity of the solid. For hematite at low pH (below 5) there was a reduction of the adsorption possibly related to the formation of positively charged species. The presence of sulfate or fulvic acid reduced the adsorption.

Influence of ph and organic substance on the adsorption of as(v) on geologic materials

Effect of redox potential on heavy metal binding forms in polluted canal sediments in Delft (The Netherlands)

Contamination of aquatic environments as a consequence of deep metal mining for Pb, Zn, Cu, Cd, and Fe is of widespread international concern. Pollution resulting from metal mining activities can result in significant environmental and ecological degradation and can pose serious risks to human health through contamination of food and drinking water. This paper provides a review of the impacts of deep metal mine water discharges on riverine sedimentology, hydrology, and ecology and explores strategies for the restoration of rivers draining historically abandoned metal mines. The review is concluded by identifying key recommendations for future research. An interdisciplinary approach, incorporating collaborative expertise and knowledge regarding sedimentological, hydrological, chemical, and ecological consequences of active and historic deep metal mining, is advocated and should be utilized for effective river basin management and the remediation and restoration of mining-impacted river systems.

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Peter Neumann-Mahlkau

Papers

The mobility of zinc, cadmium, copper, lead, iron and arsenic in ground water as a function of redox potential and pH