SBIR-STTR Award

Contaminated groundwater containing trichloroethylene and similar halogenated hydrocarbons poses a large-scale environmental challenge. Existing treatment methods are imperfect in that they are slow, expensive, fail to treat the full spectrum of groundwater contaminants, and sometimes produce even more toxic partially chlorinated chemical intermediaries. In the past decade, techniques have emerged to more effectively dechlorinate the toxic compounds in these contaminated sites. A particularly promising remediation system uses palladized iron as a reducing agent. Prior work has shown that these bimetallic powders have proven to be effective for rapidly enabling the dechlorination of these groundwater contaminants into relatively benign saturated hydrocarbons and metal salts. This surface catalyzed reaction operates fastest and with optimum volumetric efficiency when very small powders, with high surface areas, are used. Despite the market need, there is no existing low-cost source for these high surface area iron powders. To address this large market opportunity, OnMaterials, LLC, in a joint development program with ARCADIS, has performed preliminary experiments to make and test these enabling materials. These bench-scale trials used new synthesis routes that, if successfully developed, are capable of producing large quantities of relatively low-cost iron powder. Specifically, this work has produced small quantities of very high surface area (> 20 m2/g) iron colloids and larger quantities of sub-micrometer iron (surface area > 2 m2/g) suspensions. These powders then were coated with palladium and successfully used to dechlorinate hydrocarbons in a laboratory environment. The reaction kinetics of the palladized high surface area iron powders were 100-150 times those of conventional granular iron filing remediation systems. This Phase I research project will extend this work to further develop the system and demonstrate a low-cost procedure that when commercialized, can produce the needed multi-ton quantities of sub-micrometer and nanocrystalline iron powders at costs of about $50 per kilogram. The availability of these low-cost powders will enable a cost-effective and rapid protocol to help solve a widespread environmental problem. When fully implemented, the concept will provide multi-million dollar cost savings to both government agencies and industrial entities. Supplemental

Keywords:
small business, SBIR, high surface area iron powder, contaminated groundwater, trichloroethylene, halogenated hydrocarbons, palladized iron, dechlorination, remediation, EPA., INTERNATIONAL COOPERATION, TREATMENT/CONTROL, Scientific Discipline, Waste, Sustainable Industry/Business, RFA, Remediation, Technology for Sustainable Environment, Sustainable Environment, Civil/Environmental Engineering, Hazardous Waste, Environmental Engineering, cleaner production/pollution prevention, Hazardous, Treatment Technologies, bioavailability, heavy metals, iron mediated reductive transformation, hydrocarbons, iron powder, groundwater, outreach and education, remediation technologies, information transfer, contaminated sediments, community involvement, TCE, risk reduction strategies, TCE degradation, contaminated groundwater, hazardous waste treatment, technology transfer, hazardous chemicals, pollution prevention

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. Supplemental

Keywords:
small business, SBIR, contaminated groundwater, high surface area iron powder, zero valent iron, iron oxide, remediation, halogenated hydrocarbons, tricholorethylene, chlorinated solvents, toxic chemicals., POLLUTANTS/TOXICS, Scientific Discipline, Waste, Chemicals, Environmental Engineering, Environmental Chemistry, Groundwater remediation, arsenic, treatment, perchlorate, iron powder, Chromium, chlorinated solvents, groundwater contamination, contaminated groundwater, zero valent iron