Abstract: Hybrid zero-valent iron systems and methods for treating a fluid containing a contaminant that removes or reduces the concentration of contaminants, such as toxic metals, metalloids, oxyanions, and dissolved silica.

Abstract: Method for removing molybdate from a fluid comprising contacting a fluid containing molybdate with a first reactive solid comprising zero-valent iron and one or more iron oxide minerals in contact therewith; a secondary reagent in contact with the reactive solid, wherein the secondary reagent is ferrous ion; and an added secondary solid, wherein the secondary solid comprises an iron oxide mineral.

Abstract: The present inventors have discovered a novel composition, method of making the composition, system, process for treating a fluid containing a contaminant. The fluid may be aqueous. The contaminated fluid may be in the form of a suspension. The treatment reduces the concentration of the contaminant. The reduction in concentration of a contaminant may be sufficient so as to effect remediation of the fluid with respect to the contaminant. The treatment may reduce the concentration of a plurality of contaminants. The present composition, system, and process are robust and flexible. The composition includes zero valent iron, an iron oxide mineral, and ferrous iron. The ferrous iron promotes maintenance of the iron oxide mineral. The iron oxide mineral promotes the activity of the zero valent iron. The process and system may involve multiple stages. A stage may be optimized for treatment with respect to a particular contaminant.

Abstract: Compositions, methods of making the compositions, systems, and processes for treating a fluid containing a contaminant are presented. The treatment reduces the concentration of contaminants, such as such as toxic metals, metalloids, oxyanions, and dissolved silica. The reduction in concentration of a contaminant may be sufficient so as to effect remediation of the fluid with respect to the contaminant. The treatment may reduce the concentration of a plurality of contaminants. The composition typically includes zero-valent iron, an iron oxide mineral, and ferrous iron. The ferrous iron promotes maintenance of the iron oxide mineral. The iron oxide mineral may, in turn, promote the activity of the zero-valent iron. The processes and systems may involve multiple stages. A stage may be optimized for treatment with respect to a particular contaminant. Examples of contaminated fluids include aqueous fluids, such as groundwater, subsurface water, and aqueous industrial waste streams.