Not All Zero Valent Iron Powders Are The Same

Not All Zero Valent Iron Powders are the SameSince entering the environmental remediation mar-ket in 2000, Hepure’s reactive iron powders have become the most widely used micron-scale iron powders in the market with documented success-ful outcomes at more than 150 sites across North America.Hepure’s reactive iron powder lines are produced from high quality cast iron feedstock and propri-etary catalytic iron powders. The product line is available in several grades and mesh sizes for vari-ous applications. Using high quality feedstock, a proprietary grinding and pulverizing method creates reactive iron pow-ders suitable for the most demanding of remedia-tion environments. From the selection of raw materials through manu-facturing and packaging, all processes satisfy Hepure’s demanding product standards. Quality assurance testing is performed at every stage of production so that product consistency is assured. Hepure’s manufacturing goals are:Use the most reactive materials Maximize surface area to enhance reactivity Maintain limits on:--Bulk density--Chemical composition--Particle size distributionProduce the most consistent ZVI source availableFigure 1: TCE Degradation First-Order Rate Constants for Various Iron Powders When Normalized to Surface AreaFigure 2B: TCE Degradation First-Order Rate Constants Normalized to Mass Per DollarDetailed kinetics studies have revealed that not all iron powders are the same, and that Hepure reactive iron powders have excep-tional value. When these kinetic values are normalized to mass or surface area concen-trations, Ferox Flow gave the most favor-able results for the degradation of chlori-nated volatile organic compounds (cVOCs). Ferox Flow had more than twice the activity of the other iron powders (Figure 1)When we compare iron powders from Hepure’s product line with our competitors, it is clear that Hepure’s ZVI re-active iron powders are both more pure and more consis-tent. The particle size distribution is narrower, with 10% more product at the proper size and less dust. Properly sized iron powder is important to ensure ease of emplacement as well as longevity. Our competitors’ iron powders tend to have less iron and more contaminants, such as sulfur and oils, which reduce the effectiveness and suitability of the products.Table 1: Comparison of physical and chemical properties of iron powdersIn a recent evaluation of ZVI iron powders performed in his laboratories, Dr. Paul Tratnyek noted that, “The rates of TCE degradation from the column experiments in this study are surprisingly consistent with previously published work.“Ferox Flow gave the most favorable results of the ZVIs tested in this study.”Dr. Paul G. Tratnyek is a Profes-sor at Oregon Health & Science University and is a leading researcher on ZVI reactive iron powders. Hepure East--HQ130 Hickman RoadClaymont, DE 19703732.296.6652Hepure West135 Mason Circle, Suite KConcord, CA 94520732.296.6652www.hepure.com