Preliminary Desorption studies for HZ-PAN and AgZ-PAN

Welty, Amy K.; Greenhalgh, Mitchell; Garn, Troy G.

doi:10.2172/1468544

Cited by 4 publications

(8 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To further remove DMSO, the beads were placed in fresh DIW baths to help drive the diffusion process by maintaining the concentration gradient. It is likely that different polymers could be implemented in a similar technique, but PAN was selected based on success of implementing this same process to create other hybrid sorbents. ,− …”

Section: Discussionmentioning

confidence: 99%

“…X-ray absorption near-edge structure (XANES) analyses, including Bi L 3 and I L 3 edges, were also conducted on the Bi-containing materials. This work was based off our previous study evaluating pure metal wires without the porous polymer scaffold, and the 75 mass% loadings used were based off previous work on embedding active particle or powdered sorbents into PAN composites. ,− Due to kinetics limitations of iodine vapors reacting through thick (0.5 mm) wires from a separate study, small particles were selected instead for use in the current study as the active metal sites.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Iodine Capture with Metal-Functionalized Polyacrylonitrile Composite Beads Containing Ag⁰, Bi⁰, Cu⁰, or Sn⁰ Particles

Chong

Riley

Asmussen

et al. 2022

ACS Appl. Polym. Mater.

View full text Add to dashboard Cite

The capture of radioiodine from nuclear processes and the mitigation of environmental release are important topic areas of research. Some of the more commonly employed chemisorption-type iodine scavengers reported in the literature are based on metal-exchanged porous sorbents such as Ag-zeolites or metal-functionalized aerogels and xerogels. However, another option is to use zero-valent metals directly that have known high affinities for iodine gas [i.e., I2(g)]. In this study, fine metal particles of Ag0, Bi0, Cu0, and Sn0 were embedded in porous polyacrylonitrile (PAN) substrates at 75 mass% metal loadings within the form of ellipsoidal beads with maximum diameters of ∼2–3 mm. These composite beads showed extremely high iodine loadings that are directly related to the metal particle loadings. The X-ray diffraction (XRD) analyses of Ag0, Bi0, Cu0, and Sn0 particles as well as metal-PAN composite beads reacted with iodine gas at 120 ± 1 °C showed phases of AgI, BiI3, CuI, and SnI4, respectively. For the Ag-PAN, Cu-PAN, and Sn-PAN beads, no other crystalline peaks were observed in XRD for unreacted metal or oxidized metals after 48 h in saturated I2(g) at 120 ± 1 °C, whereas unreacted metallic Bi0 was observed within the Bi-PAN composites. However, after a 72 h exposure at 120 ± 1 °C, both the Bi0 particles and the Bi-PAN composites showed full conversion from Bi0 to BiI3 with XRD. Comparisons between mass uptake data and X-ray absorption spectroscopy were used to better understand the phase distribution of the Bi phases present in the Bi-PAN+I composites. The iodine loadings (mg iodine per g sorbent, or q e) for these materials were 1120 (Ag-Particle), 1382 (Bi-Particle-72h), 1033 (Cu-Particle), 3000 (Sn-Particle), 753 (Ag-PAN), 1012 (Bi-PAN-72h), 1457 (Cu-PAN), and 1669 (Sn-PAN). It is possible that inexpensive sorbents such as these could be deployed to help limit or prevent release of radioiodine to the environment.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Iodine Capture with Metal-Functionalized Polyacrylonitrile Composite Beads Containing Ag⁰, Bi⁰, Cu⁰, or Sn⁰ Particles

Chong

Riley

Asmussen

et al. 2022

ACS Appl. Polym. Mater.

View full text Add to dashboard Cite

show abstract

“…The ability to remove adsorbed species efficiently has been demonstrated repeatedly and consistently. Previous studies suggested that reducing the rate of temperature increase during desorption may provide an opportunity for further separation of Xe from Kr and air adsorbed on the AgZ-PAN (Welty, Greenhalgh, & Garn, 2017). With careful temperature control during desorption, nearly complete separation of Kr from Xe was achieved (Figure 1).…”

Section: Agz-pan Desorptionmentioning

confidence: 90%

“…Recent engineering studies (Jubin, et al, 2016) (Jubin, et al, 2017) indicated a need for desorption data in order to advance the technological readiness for development of integrated off-gas treatment systems. To that end, preliminary desorption studies were carried out last year to guide further desorption research (Welty, Greenhalgh, & Garn, 2017). This series of tests is a continuation of those studies to further characterize desorbed gases.…”

Section: Introductionmentioning

confidence: 99%

HZ-PAN and AgZ-PAN Desorption Characterization

Welty

Greenhalgh

Garn

et al. 2018

View full text Add to dashboard Cite

While previous research focused on adsorption of Kr and Xe on HZ-PAN and AgZ-PAN, recent focus has shifted to desorption. Preliminary testing was completed last year, providing valuable information to guide further research.Previous isotherm studies indicated that thermal swing operations, along with a sweep gas, are required for effective desorption of captured species from both AgZ-PAN and HZ-PAN. This series of tests focused on characterizing the bulk gases removed from each sorbent and relative separation of Kr and Xe from each other and from the bulk air. Stepwise thermal desorption resulted in 99-100% separation of Xe from Kr, and 77-83% separation of Kr from air while concentrating Xe seven to tenfold and Kr three to fivefold from initial feed stream compositions. Previous isothermal studies of both sorbents have shown that sorbent capacity is proportional to feed gas concentration. Therefore, it is anticipated that additional HZ-PAN columns operated in series will further concentrate and purify the final Kr stream with higher efficiency. It is expected that Xe will be released to atmosphere after desorption. However, it could also be purified further with more AgZ-PAN columns in series. Further testing should be done to determine maximum purity achievable for both Kr and Xe. Additionally, renewed focus on increasing Xe capacity on AgZ-PAN and Kr capacity on HZ-PAN is recommended.

show abstract

“…First, the desorption processes for AgZ-PAN and HZ-PAN have not been optimized. To date, the majority of desorption experiments have been performed with a helium sweep gas (Welty et al 2017b).…”

Section: Kr/xe Separations Using Engineered Zeolitesmentioning

confidence: 99%

Performance Criteria for Capture and/or Immobilization Technologies (Revision 1)

Bruffey¹,

Riley

Soelberg

et al. 2020

View full text Add to dashboard Cite

The capture and subsequent immobilization of regulated volatile radionuclides from the off-gas streams of a used nuclear fuel (UNF) reprocessing facility has been a topic of substantial research interest for the US Department of Energy and its international counterparts. Removal of specific radionuclides from the plant effluent streams before discharge to the environment is required to meet regulations set forth by the US Environmental Protection Agency. Upon removal, the radionuclides, as well as associated sorbents that cannot be regenerated in a cost-effective manner, are destined for conversion to a waste form. Research in separation and capture methodologies has included a wide range of technology types, and studies of waste forms are correspondingly diverse. In considering the future development and implementation of both sorbents and waste forms, it is necessary to identify benchmark measures of performance to objectively evaluate each sorbent system or waste form.

show abstract

Preliminary Desorption studies for HZ-PAN and AgZ-PAN

Cited by 4 publications

References 1 publication

Iodine Capture with Metal-Functionalized Polyacrylonitrile Composite Beads Containing Ag⁰, Bi⁰, Cu⁰, or Sn⁰ Particles

Iodine Capture with Metal-Functionalized Polyacrylonitrile Composite Beads Containing Ag⁰, Bi⁰, Cu⁰, or Sn⁰ Particles

HZ-PAN and AgZ-PAN Desorption Characterization

Performance Criteria for Capture and/or Immobilization Technologies (Revision 1)

Contact Info

Product

Resources

About

Preliminary Desorption studies for HZ-PAN and AgZ-PAN

Cited by 4 publications

References 1 publication

Iodine Capture with Metal-Functionalized Polyacrylonitrile Composite Beads Containing Ag0, Bi0, Cu0, or Sn0 Particles

Iodine Capture with Metal-Functionalized Polyacrylonitrile Composite Beads Containing Ag0, Bi0, Cu0, or Sn0 Particles

HZ-PAN and AgZ-PAN Desorption Characterization

Performance Criteria for Capture and/or Immobilization Technologies (Revision 1)

Contact Info

Product

Resources

About

Iodine Capture with Metal-Functionalized Polyacrylonitrile Composite Beads Containing Ag⁰, Bi⁰, Cu⁰, or Sn⁰ Particles

Iodine Capture with Metal-Functionalized Polyacrylonitrile Composite Beads Containing Ag⁰, Bi⁰, Cu⁰, or Sn⁰ Particles