Adsorbents and adsorption models for capture of Kr and Xe gas mixtures in fixed-bed columns

Ladshaw, Austin; Wiechert, Alexander; Welty, Amy K.; Lyon, Kevin L.; Law, Jack D.; Jubin, Robert Thomas; Tsouris, Costas; Yiacoumi, Sotira

doi:10.1016/j.cej.2019.122073

Cited by 13 publications

(9 citation statements)

References 36 publications

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“…We further investigated the gas mixture separation via simulated breakthrough experiments. Herein, we used a software associated with the 3P mixSorb Manager instrument named 3P Simulation to simulate the breakthrough of Xe/Kr (20/80), Xe/Ar (1/99), and Xe/N 2 (1/99). , Before monitoring the breakthrough curves, we fitted the single-component adsorption curves by the equation named DS langmuirSIPS (the fitted parameters are displayed in Table S4) and then chose the ISAT method with DSLAISIPS model to simulate the breakthrough curves. The coefficients involved in the simulation are shown in Tables S5–S7.…”

Section: Resultsmentioning

confidence: 99%

Robust Bimetallic Ultramicroporous Metal–Organic Framework for Separation and Purification of Noble Gases

et al. 2020

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Noble gases, especially krypton (Kr) and xenon (Xe), are widely applied in diverse fields. Developing new techniques and adsorbents to separate and purify Kr and Xe is in high demand. Herein, we reported a bimetallic metal–organic framework (MOF) (NKMOF-1-Ni) which possesses a narrow pore size (5.36 Å) and ultrahigh stability (e.g., stable in water for 1.5 years). Gas sorption measurements revealed that this MOF possessed much higher uptake for Xe than for Kr, Ar, or N2 at room temperature in all pressure ranges. The calculation of adsorption isosteric heat and Grand Canonical Monte Carlo simulation verified that NKMOF-1-Ni had a stronger interaction with Xe than other tested gases. The results of ideal adsorbed solution theory selectivity and simulated breakthrough further showed that NKMOF-1-Ni had an outstanding separation performance of Xe/Kr, Xe/Ar, and Xe/N2. This study provides important guidance for future research to synthesize ideal sorbents to separate noble gases.

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Section: Resultsmentioning

confidence: 99%

Robust Bimetallic Ultramicroporous Metal–Organic Framework for Separation and Purification of Noble Gases

et al. 2020

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“…Aging simulations are performed with the DG-OSPREY model, which is developed at the Georgia Institute of Technology . DG-OSPREY is, in turn, built within the Multiphysics Object Oriented Simulation Environment (MOOSE) modeling framework developed at the Idaho National Laboratory .…”

Section: Methodsmentioning

confidence: 99%

“…Domain discretization may be performed using either continuous or discontinuous finite element methods. Discontinuous methods are less oscillatory for problems derived from conservation laws and, as such, are used in DG-OSPREY . The non-linear system of equations produced from domain discretization is solved iteratively using the Preconditioned Jacobi Free-Newton Krylov (PJFNK) method.…”

Section: Methodsmentioning

confidence: 99%

“…Additionally, the recovery of usable materials from SNF reduces waste from and increases the sustainability of nuclear energy. SNF, nevertheless, contains a number of radioactive fission byproducts, which are volatilized during reprocessing including iodine-129 in both organic and inorganic forms, tritium, carbon-14, krypton-85, and xenon-135 . Of these species, iodine is the most important as a result of its long half-life (∼15.7 million years), which allows for accumulation in the environment.…”

Section: Introductionmentioning

confidence: 99%

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Capture of Iodine from Nuclear-Fuel-Reprocessing Off-Gas: Influence of Aging on a Reduced Silver Mordenite Adsorbent after Exposure to NO/NO₂

Wiechert

Ladshaw

Moon

et al. 2020

ACS Appl. Mater. Interfaces

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Iodine radioisotopes released during nuclear fuel reprocessing must be removed from the off-gas stream before discharge. One promising material for iodine capture is reduced silver mordenite (Ag 0 Z). Nevertheless, the adsorbent's capacity will degrade, or age, over time when the material is exposed to other off-gas constituents. Though the overall impact of aging is known, the underlying physical and chemical processes are not. To examine these processes, Ag 0 Z samples were prepared and aged in 2% NO 2 in dry air and in 1% NO in N 2 gas streams at 150 °C for up to six months. Aged samples were then characterized using scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and X-ray absorption spectroscopy. These techniques show that aging involves two overarching processes: (i) oxidation of the silver nanoparticles present in Ag 0 Z and (ii) migration of oxidized silver into the mordenite's inner network. Silver on the nanoparticle's surface is oxidized through adsorption of O 2 , NO, and NO 2 . Raman spectroscopy and X-ray absorption spectroscopy indicate that nitrates are the primary products of this adsorption. Most of these nitrates migrate into the interior of the mordenite and exchange at framework binding sites, returning silver to its unreduced state (AgZ). The remaining nitrates exist at a persistent concentration without aggregating into bulk-phase AgNO 3 . X-ray absorption spectroscopy results further indicate that iodine adsorption occurs on not just Ag 0 Z but also on AgZ and a portion of the nitrates in the system. AgZ adsorbs a sizable quantity of iodine early in the aging process, but its capacity drops rapidly over time. For well-aged samples, nitrates are responsible for up to 95% of mordenite's iodine capacity. These results have enhanced our understanding of the aging process in silver mordenite and are expected to guide the development of superior adsorbents for the capture of radioactive iodine from reprocessing off-gas.

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“…Based on our experimental observations, several factors influence the selectivity of weakly interacting gases within MOFs. For example, MOFs with unsaturated open metal sites offer stronger adsorbate–MOF interactions; however, these adsorbents are not selective for noble gases when other competing gases such as H 2 O and CO 2 are present. − Similarly, other MOF attributes studied include ligand polarizability, hydrophilic and hydrophobic surface functionalities, surface area, pore size, presence of metal nanoparticles, and temperature. − Overall, all of these factors play a significant role in the ability of these materials to separate noble gases from each other and from air. − …”

Section: Introductionmentioning

confidence: 99%

Metal–Organic Framework–Polyacrylonitrile Composite Beads for Xenon Capture

Riley

Chong

Kuang

et al. 2020

ACS Appl. Mater. Interfaces

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Mechanically robust forms of HKUST-1 metal− organic frameworks (MOFs) were fabricated by embedding the MOF crystals in a passive polyacrylonitrile (PAN) matrix at different MOF loadings of 10−90 mass %. PAN is highly porous and acts as a scaffold that holds the active MOF adsorbent in place. These MOF−PAN composites were then evaluated for capturing Xe. Data presented herein show that the PAN matrix does not notably interfere with the Xe capture process, where the Xe capacities scale somewhat linearly with the increase in MOF loadings within the composites. Also, γ radiation exposures to the composites revealed that they are highly tolerant to these types of radiation fields.

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Adsorbents and adsorption models for capture of Kr and Xe gas mixtures in fixed-bed columns

Cited by 13 publications

References 36 publications

Robust Bimetallic Ultramicroporous Metal–Organic Framework for Separation and Purification of Noble Gases

Robust Bimetallic Ultramicroporous Metal–Organic Framework for Separation and Purification of Noble Gases

Capture of Iodine from Nuclear-Fuel-Reprocessing Off-Gas: Influence of Aging on a Reduced Silver Mordenite Adsorbent after Exposure to NO/NO₂

Metal–Organic Framework–Polyacrylonitrile Composite Beads for Xenon Capture

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Adsorbents and adsorption models for capture of Kr and Xe gas mixtures in fixed-bed columns

Cited by 13 publications

References 36 publications

Robust Bimetallic Ultramicroporous Metal–Organic Framework for Separation and Purification of Noble Gases

Robust Bimetallic Ultramicroporous Metal–Organic Framework for Separation and Purification of Noble Gases

Capture of Iodine from Nuclear-Fuel-Reprocessing Off-Gas: Influence of Aging on a Reduced Silver Mordenite Adsorbent after Exposure to NO/NO2

Metal–Organic Framework–Polyacrylonitrile Composite Beads for Xenon Capture

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Product

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Capture of Iodine from Nuclear-Fuel-Reprocessing Off-Gas: Influence of Aging on a Reduced Silver Mordenite Adsorbent after Exposure to NO/NO₂