Zero-valent iron is cheap, environmentally innocuous, and effective at reducing chlorinated organics. It has, as a result, become a popular candidate for remediating aquifers contaminated with trichloroethylene and other halogenated pollutants. In this paper, we discuss one such system, where iron nanoparticles are synthesized and incorporated into polyvinyl alcohol membranes, forming water-permeable barriers to these pollutants. These barriers are tested against a variety of contaminants, including carbon tetrachloride, copper, and chromate. The success (and, in some cases, failure) of these membranes offer several insights regarding the design and application of reactive barrier films for environmental remediation. These iron membranes are especially effective at blocking copper, potentially opening a new avenue of metal / radionuclide remediation applications. They might also, by prudent choice of polymer, be made into preventative barriers which would line potential pollution sites such as landfills or tank farms. The economic advantages of using larger iron particles are clear, but the drawbacks due to reduced effectiveness are not so straightforward and may, in fact, change with the application. We build upon our existing theory to predict how the particle size (and hence, the effective reaction rate of the system) should affect contaminant diffusion through the membranes.
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