Investigating Metal-Organic Frameworks as Clean-Up Agents for Nuclear Waste
September 16, 2015
Sanjit Ghose, center, co-authored two papers that describe metal-organic frameworks capable of adsorbing xenon and krypton.
One of the most versatile and widely applicable classes of material being studied today are metal-organic frameworks, or MOFs, and the studies are showing promising uses. MOFs are characterized by metal ions or metal-ion clusters that are linked together with organic molecules forming ordered crystal structures that contain tiny cage-like pores with diameters of two nanometers or less.
MOFs can be thought of as highly specialized and customizable sieves. By designing them with pores of a certain size, shape, and chemical composition, researchers can tailor them for specific purposes.
A few of the many, many possible applications for MOFs are storing hydrogen in fuel cells, capturing environmental contaminants, or temporarily housing catalytic agents for chemical reactions.
At Brookhaven Lab researchers have been studying MOFs designed for use in the separation of waste from nuclear reactors, which results from the reprocessing of nuclear fuel rods. Two waste products in particular have been targeted: the noble gases xenon (Xe) and krypton (Kr).
There are compelling reasons to separate Xe and Kr from the nuclear waste stream. For one, because they have very different half-lives – about 36 days for Xe and nearly 11 years for Kr – pulling out the Xe greatly reduces the amount of waste that needs to be stored long-term before it is safe to handle. Additionally, the extracted Xe can be used for industrial applications such as in commercial lighting and as an anesthetic. This research may also help scientists determine how to create MOFs that can remove other materials from the nuclear waste stream and expose the remaining unreacted nuclear fuel for further reuse. This could lead to much less overall waste that must be stored long-term and a more efficient system for producing nuclear energy, the source of about 20 percent of the electricity in the U.S.
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2015-5944 | INT/EXT | Newsroom