Superfund Research Program
Sub-Micrometer Zero Valent Metal for in situ Remediation of Contaminated Aquifers
Project Leader: John Freim
Grant Number: R43ES014114
Funding Period: Phase I: 2006-2007
Contaminated aquifers are a widespread problem and serious health risks arise when pollutants are introduced into the drinking water supply. Recently, injectable zero valent metals have emerged as a methodology to decontaminate groundwater containing chlorinated solvents and toxic metals. Today's zero valent metal remediation schemes typically employ microscale iron that has been engineered for other markets. Fundamental shortcomings of microscale product include limited underground mobility and the propensity to produce also-toxic reaction products. Recently, sub-micrometer and nanocrystalline powders have emerged as alternatives to microscale product. Bench scale experiments show exceptional reactivity, with kinetic rate constants that scale with the powder's high surface area. However, commercial use has been limited by several factors that include product cost and less than anticipated mobility. To address the market need, OnMaterials has developed Z-Loy, a lower cost and non-aggregated sub-micrometer zero valent metal product line. Z-Loy is manufactured using a mechanical assembly process that deposits zero valent metals onto the surface of electrochemically active, sub-micrometer carrier particles. Unlike other NZVI synthesis protocols the procedure is carried out in a non-aqueous environment. This provides two distinct advantages; one is the ability to limit aggregation and the second is the ability to use more reactive zero valent metal compositions. Discreet particles enable improved mobility while more reactive metals can better accomplish the direct conversion of common chlorinated contaminants to non-toxic substances. The Phase I work has been designed to better understand and demonstrate the product's performance and to further its utility.
In prior decades chlorinated chemicals were used for cleaning and degreasing. Due to a limited natural attenuation, numerous underground locations contain concentrations in excess of federal drinking water standards. Adverse health effects associated with exposure to chlorinated hydrocarbons include damage to the nervous system, liver dysfunction, and an increased cancer risk. The technology being developed here provides an innovative and lower cost solution for treating contaminated aquifers.