Adsorption of Noble Gases on Silver-mordenite

Munakata, Kenzo; Kanjo, Seigo; Yamatsuki, Satoshi; Koga, Akihiro; Ianovski, Dmitri

doi:10.3327/jnst.40.695

Cited by 22 publications

(33 citation statements)

References 8 publications

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“…Previous research has shown that NaA and NaX zeolites are selective adsorbents for Xe over Kr, with selectivities of approximately four to six, but they have low Xe capacities. [106][107][108][109] The storage of noble gases was demonstrated in some MOFs, though research to date is somewhat limited. 15 Recently, Thallapally et al 110 reported that Ni/DOBDC has a Xe capacity of 4.16 mol kg −1 at 100 kPa and 298 K. Moreover, Liu et al 29 used a column breakthrough method to study the low concentration Xe and Kr adsorption in MOFs.…”

Section: Radioactive Gas Immobilizationmentioning

confidence: 99%

Metal‐Organic Frameworks: Harmful Gas Removal

Liu

McGrail

Strachan

et al. 2014

Encyclopedia of Inorganic and Bioinorganic Chemistry

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Metal–organic frameworks (MOFs) have been considered to be novel adsorbents for a variety of applications, because of their high surface areas, large pore volumes, tunable pore geometries, and versatile chemical compositions. Besides their applications in energy gas storage, such as H 2 and CH 4 , harmful gas removal has become an important potential area for MOFs applications. This chapter reviews recent research related to four different types of harmful gas adsorption in MOFs, including greenhouse gases such as CO 2 , inorganic toxic gases such as SO x , NO x , and NH 3 ; volatile organic compounds such as benzene and formaldehyde; and radioactive gases such as Xe, Kr, and I 2 . This information is organized in a way that will attempt to introduce this attractive research area to a broad audience, as well as to reveal some trends and significant discoveries to the researchers who are interested in this area. Obviously, removing harmful gases can provide a cleaner and safer living environment to human beings and other creatures. MOFs as novel adsorbents possess advantages, such as high gas adsorption capacities and selectivities, as well as adjustable properties to suit specific needs. However, more fundamental work is still necessary to understand this topic better, and some challenges, such as cost and stability, are in the way of applying MOFs to practical applications.

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Section: Radioactive Gas Immobilizationmentioning

confidence: 99%

Metal‐Organic Frameworks: Harmful Gas Removal

Liu

McGrail

Strachan

et al. 2014

Encyclopedia of Inorganic and Bioinorganic Chemistry

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show abstract

“…Thus, a process to remove these gases at much higher temperatures would be advantageous and cost effective, especially if the process could operate at close to ambient conditions. Zeolites and activated carbons have been tested for Xe and Kr separation with selectivities of approximately four to six with very low capacities (0.5 -2 mmol/g) (Jameson et al 1997;Bazan et al 2011;Munakata et al 2003).…”

Section: Tablesmentioning

confidence: 99%

Initial proof-of-principle for near room temperature Xe and Kr separation from air with MOFs

Thallapally

Strachan

2012

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SUMMARYMaterials were developed and tested in support of the U.S. Department of Energy's Office of Nuclear Energy, Fuel Cycle Technology Separations and Waste Forms Campaign. Specifically, materials are being developed for the removal of xenon (Xe) and krypton (Kr) from gaseous products of nuclear fuel treatment.During fiscal year 2012, three metal organic framework (MOF) structures were investigated in greater detail for the removal and storage of Xe and Kr from air at room temperature. Breakthrough measurements on a nickel-based MOF indicate this material could capture and separate parts per million by volume (ppmv) levels of Xe (400 ppmv) from air (40 ppmv Kr, 78% N 2 , 21% O 2 , 0.9% Ar, and 0.03% CO 2 ). Similarly, the selectivity of a fluorinated MOF can be changed from Xe > Kr to Xe < Kr simply by changing the temperature over a narrow range (-30 °C). Estimates were made for the cost of bulk quantities of MOFs and compared to other capture materials.

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“…Zeolite has been found to exhibit a relatively high loading for noble gases (Ianovski et al, 2002;Munakata et al, 2003;Webster et al, 1999). It has been shown that krypton can be encapsulated in the zeolite structure by a sintering process where micropores of the zeolite are sealed (Gombert, 2007).…”

Section: Current Status Of Off-gas Treatment In Fuel Reprocessingmentioning

confidence: 99%

“…Mordenite, especially Ag-mordenite, has been considered as a candidate for adsorption of radioactive noble gases (e.g., Ianovski et al, 2002;Munakata et al, 2003Munakata et al, , 2006Munakata et al, , 2008. It seems that materials developed at Sandia National Laboratories can outperform modernite-A and mordenite-N in terms of adsorption capacities and adsorption kinetics, in addition to their inexpensive nature.…”

Section: Adsorption Kineticsmentioning

confidence: 99%

Development of a new generation of waste form for entrapment and immobilization of highly volatile and soluble radionuclides.

Rodriguez¹,

Bencoe²,

Brinker³

et al. 2010

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The United States is now re-assessing its nuclear waste disposal policy and re-evaluating the option of moving away from the current once-through open fuel cycle to a closed fuel cycle. In a closed fuel cycle, used fuels will be reprocessed and useful components such as uranium or transuranics will be recovered for reuse. During this process, a variety of waste streams will be generated. Immobilizing these waste streams into appropriate waste forms for either interim storage or long-term disposal is technically challenging. Highly volatile or soluble radionuclides such as iodine ( 129 I) and technetium ( 99 Tc) are particularly problematic, because both have long half-lives and can exist as gaseous or anionic species that are highly soluble and poorly sorbed by natural materials. Under the support of Sandia National Laboratories (SNL) LaboratoryDirected Research & Development) (LDRD), we have developed a suite of inorganic nanocomposite materials (SNL-NCP) that can effectively entrap various radionuclides, especially for 129 I and 99 Tc. In particular, these materials have high sorption capabilities for iodine gas. After the sorption of radionuclides, these materials can be directly converted into nanostructured waste forms. This new generation of waste forms incorporates radionuclides as 3 4 nano-scale inclusions in a host matrix and thus effectively relaxes the constraint of crystal structure on waste loadings. Therefore, the new waste forms have an unprecedented flexibility to accommodate a wide range of radionuclides with high waste loadings and low leaching rates.Specifically, we have developed a general route for synthesizing nanoporous metal oxides from inexpensive inorganic precursors. More than 300 materials have been synthesized and characterized with x-ray diffraction (XRD), BET surface area measurements, and transmission electron microscope (TEM). The sorption capabilities of the synthesized materials have been quantified by using stable isotopes I and Re as analogs to 129 I and 99 Tc. The results have confirmed our original finding that nanoporous Al oxide and its derivatives have high I sorption capabilities due to the combined effects of surface chemistry and nanopore confinement. We have developed a suite of techniques for the fixation of radionuclides in metal oxide nanopores. The key to this fixation is to chemically convert a target radionuclide into a less volatile or soluble form. We have developed a technique to convert a radionuclide-loaded nanoporous material into a durable glass-ceramic waste form through calcination. We have shown that mixing a radionuclide-loaded getter material with a Na-silicate solution can effectively seal the nanopores in the material, thus enhancing radionuclide retention during waste form formation. Our leaching tests have demonstrated the existence of an optimal vitrification temperature for the enhancement of waste form durability. Our work also indicates that silver may not be needed for I immobilization and encapsulation.

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Adsorption of Noble Gases on Silver-mordenite

Cited by 22 publications

References 8 publications

Metal‐Organic Frameworks: Harmful Gas Removal

Metal‐Organic Frameworks: Harmful Gas Removal

Initial proof-of-principle for near room temperature Xe and Kr separation from air with MOFs

Development of a new generation of waste form for entrapment and immobilization of highly volatile and soluble radionuclides.

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