Affordable, Large Scale Manufacturing of High Surface Area Iron Powder

Contaminated groundwater presents a widespread environmental challenge in America today. Existing treatment methods are imperfect in that they are either slow, expensive, or unable to treat the full spectrum of groundwater contaminants. Prior work has demonstrated that zero valent iron can detoxify groundwater contaminated with halogenated hydrocarbons and other toxic chemicals. The beneficial chemical reactions occur on the particle surface so an ideal, kinetically active powder will offer a large surface area per unit mass. Traditional iron materials are inexpensive but contain coarse particles and provide a low surface area of only 0.1 to 0.4 m2/g of powder. Accordingly, these powders react slowly and often are unable to treat the full spectrum of groundwater contaminants. Recently, nanocrystalline iron powders with a surface area of greater than 10 m2/g have been marketed, but these materials either are prohibitively expensive, not available in large quantities, or contain a significant amount of nonreactive iron oxide. The goal of this research project is to apply OnMaterials' expertise in powder synthesis and processing to produce a lower-cost, high-surface area, zero valent iron for the remediation marketplace. A series of experiments were performed that identified materials and processing conditions to produce iron with a surface area 10-20 times greater than existing low-cost powders. The OnMaterials synthesis process also is capable of producing powder containing embedded secondary metals. These multimetallic materials are beneficial because they catalyze the production of hydrogen gas that increases the reaction rate. When the benefits of the multimetallic system were coupled with the high surface area, OnMaterials' powder provided very rapid reaction kinetics. When a small amount of powder was added to an aqueous tricholorethylene solution, OnMaterials powder accomplished the removal of all chlorinated compounds in less than 1 day. In contrast, commercially available iron powder showed negligible reactivity after 1 week in the same solution. The highly reactive powder will allow for the end user to use a lesser powder quantity to remediate a given amount of contaminant with a concurrent reduction in application costs. The high reactivity also will allow for the treatment of reduction-resistant groundwater contaminants. When successfully developed, scaled, and commercialized, the product can positively impact the $5 billion per year remediation marketplace, not only for chlorinated solvents, but also for other toxic chemicals, including chromates, arsenic, and perchlorate.