State Water Resources Research Institute Program


Project ID: 2007ND150B
Title: Effective Delivery of Iron Nanoparticles by Amphiphilic Polysiloxane Graft Copolymeric Vehicles for Groundwater Remediation
Project Type: Research
Start Date: 3/01/2007
End Date: 2/29/2008
Congressional District: 1
Focus Categories: Groundwater, Treatment
Keywords: Iron nanoparticles, Groundwater remediation, Delivery vehicles, copolymers
Principal Investigator: Bezbaruah, Achintya Nayan (North Dakota State University)
Federal Funds: $ 2,000
Non-Federal Matching Funds: $ 4,000
Abstract: An increasing number of laboratory and field studies illustrate the potential of metal particles for degrading organic and inorganic species susceptible to reduction reactions. Recently, emphasis on metal particle use has changed from regular macro and micro filings/particles to metal and bimetal nanoparticles. Various chlorinated aliphatic hydrocarbons and toxic metals can be remediated using metal nanoparticles such as zero valent iron (Fe°) nanoparticles (ZVIN). The effectiveness of a remediation depends on the ability to access the contaminants with the metal nanoparticles. Fe° nanoparticles, for example, are highly reactive and react rapidly with surrounding media in the subsurface (dissolved oxygen and/or water). Thus, significant loss of reactivity occurs before the particles are able to reach the target contaminant. To overcome this problem of oxidation by dissolved oxygen, the in-situ application of Fe° particles is preceded by injection of a carbon source (e.g., liquid molasses) into the aquifer to render the site anoxic. However, this involves a major financial investment and is time consuming. Thus, there is a need to develop effective and efficient methods to protect the metal nanoparticles from oxidation prior to their contact with the target contaminant. Another important characteristic needed in metal nanoparticles for remediation is their ability to individually disperse and suspend in water. Fe° nanoparticles tend to flocculate when added to water due to interparticle Van der Waal interactions. Flocculation reduces the effective surface area of the metal and causes precipitation of the metal from the aqueous phase. Thus, there is a need for methods to form stable colloidal suspensions of metal nanoparticles in water. In addition, there is a need to create an affinity between the metal nanoparticles and the water/contaminant interface. Maximum efficiency of the remediation approach will only be realized if the metal nanoparticles effectively migrate to the contaminant or the water/contaminant interface. The objective of this study is to modify the iron nanoparticle surfaces using amphiphilic polysiloxane graft copolymers (APGCs) for effective groundwater remediation. The study has the potential to develop a new polymeric delivery vehicle for iron nanoparticles for groundwater remediation. The synthesis, characterization, and analysis phases of the polymeric delivery vehicle development process will result in fundamental knowledge on the behavior of the polymer coated nanoparticles. Kinetic studies for TCE/ As(III)/ RDX will help us in quantifying the advantages and disadvantages of using polymer coated iron nanoparticles for remediation.

Progress/Completion Report, PDF

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