The Effect of Surface Coatings on the Environmental and Microbial Fate of Nanoiron and Feoxide Nanoparticles
|Principal Investigator||Gregory V. Lowry|
|Institution||Carnegie Mellon University , Chapman University , Rice University|
|Relevance to Implications||High|
|Class of Nanomaterial||Engineered Nanomaterials|
|Broad Research Categories||
Generation, Dispersion, Transformation etc.
|Anticipated Total Funding||$400,000.00|
|Anticipated End Year||2009|
Description: Responsible use of manufactured nanomaterials in environmental applications (e.g. nanoiron) and prudent management of the associated risks requires a fundamental understanding of their mobility, bioavailability, and impacts on a wide variety of organisms. We lack a fundamental understanding of the environmental and microbial fate of nanoiron and its metal oxide oxidation product (magnetite) under environmental conditions. It is also not clear what effect surface coatings present on nanoiron (and many other NPs) will have on the rate and extent of oxidation, their mobility after reaction (and hence potential exposure risk), their interactions with soil bacteria, their effect on the soil microbial health and diversity under natural environmental conditions, or on human health. Objective: The study objectives are to determine the effect of common NP surface coatings on nanoiron reactivity, mobility, fate, and effect on soil bacteria. This will be accomplished by: 1) examining the fate of coated and uncoated nanoiron and Fe-oxide NPs in active and sterilized soil microcosms; 2) determining the mobility of fresh and reacted NPs in soil columns; 3) evaluating the impact of surface coatings on NP-bacteria interactions and toxicity; and 4) evaluating the changes in microbial ecology due to nanoiron and Fe-oxide NP exposure. NP mobility and fate in the environment, negative or beneficial interactions with soil bacteria, and reactivity with soil contaminants are controlled by particle surface chemistry. Adsorbed surface coatings, e.g. polymers, polyelectrolytes, and surfactants dictate the interactions of NPs with environmental media and microbes and therefore can be used to control their environmental fate and potential toxicity, and to enhance synergistic biogeochemical interactions of nanoiron with soil microorganisms such as biostimulation by cathodic hydrogen production and reductive dissolution of inert Fe(III) oxides that passivate the nanoiron surface. Expected Results: This project will provide fundamental information on the effects of typical NP surface coatings on the fate and mobility of nanoiron and Fe-oxide NPs after exposure under realistic environmental conditions, and the impact of these surface coatings on microbial processes important to site remediation and ecosystem health. This will enable the synthesis and use of ecofriendly surface-coated nanoiron and Fe-oxide NPs, and enable rational risk-based decision making regarding their production, use, and disposal.