CAREER: Reactivity of Green Rust Compounds in Natural and Engineered Systems

University Of Iowa, Iowa City IA

Investigators

Abstract

9983719 Scherer It is estimated that there are between 300,000 and 400,000 sites in the USA highly contaminated with a wide variety of toxic chemicals. Conventional cleanup practices have proved relatively ineffective and prohibitively costly, spurring a paradigm shift towards in situ cleanup technologies that rely on natural processes that act with little or no human intervention to reduce the mass, toxicity or mobility of contaminants in soil or groundwater. Recently the potential role of iron mineral surfaces in these systems has been recognized. Specifically, green rusts (a group of reduced iron compounds) has been shown to degrade a wide variety of priority pollutants and may be contributing to the degradation of pollutants in natural and engineered systems. The goal of this research project is to improve the assessment and performance of in situ remediation technologies by evaluating the potential role of green rusts. This will be accomplished by: (1) quantifying the reactivity of green rusts with a series of environmental contaminants, (2) investigating the mechanism by which green rusts transform contaminants and (3) determining the prevalence of green rusts in soil and groundwater. The prevalence and reactivity of green rusts will be evaluated using a combination of indirect (batch and column reactors) and direct (electrochemical and spectroscopic) methods. The kinetic data derived from this work will provide the first set of rate coefficients for reduction of these contaminants by green rusts. A number of subsurface environments will be sampled and analyzed and the oxides that form in column experiments will be characterized. The insights derived from these investigations will provide an improved basis for predicting the natural attenuation of contaminants and assessing the significance of green rusts in the performance of iron-based remediation technologies. The multifaceted nature of this research provides an excellent environment to introduce undergraduate students to the field of Environmental Engineering. A pilot program involving Undergraduate Women in Environmental Engineering Research will be launched to improve the retention, recruitment and advancement of women in engineering. By exposing women undergraduates to an active research environment and providing female graduate student and faculty role models, the PI hopes to retain and recruit bright, intellectually capable women in a field in which they are currently under-represented. ***