Selective adsorption of Pd(II) over Ag(I) in nitric acid solutions using nitrogen-donor-type adsorbents

Suzuki, Tomoya*; Otsubo, Ukyo*; Ogata, Takeshi*; Shiwaku, Hideaki; Kobayashi, Toru; Yaita, Tsuyoshi; Matsuoka, Mitsuaki*; Murayama, Norihiro*; Narita, Hirokazu*

Separation and Purification Technology, 308, p.122943_1 - 122943_7, 2023/03

https://doi.org/10.1016/j.seppur.2022.122943

HNO leaching is used in recycling Pd metal from spent products that primarily contain Ag, and most Pd residues are separated from solutions containing Ag(I). However, a small amount of Pd(II) often remains in these Ag(I) solutions. Therefore, the separation of Pd(II) and Ag(I) in HNO solutions is essential to promote efficient Pd recycling. In this study, the separation of Pd(II) and Ag(I) in HNO solutions was investigated using four N-donor-type adsorbents functionalized with amine (R-Amine), iminodiacetic acid (R-IDA), pyridine (R-Py), or bis-picolylamine (R-BPA). R-Amine, R-IDA, and R-Py selectively adsorbed Pd(II) over Ag(I), Cu(II), Ni(II), and Fe(III) from HNO solutions (0.3-7 M), but R-Amine exhibited a lower Pd adsorption efficiency. In contrast, 90% of Pd(II), Ag(I), and Cu(II) were adsorbed by R-BPA over the entire range of HNO concentrations. Structural analyses of the adsorbed metal ions using Fourier transform infrared spectroscopy and extended X-ray absorption fine structure spectroscopy revealed the separation mechanisms of the N-donor-type adsorbents. Pd(II) adsorption on R-IDA, R-Py, and R-BPA occurred via Pd(II) coordination of the functional groups (iminodiacetic acid, pyridine, and bis-picolylamine, respectively), whereas that on R-Amine occurred via anion exchange of NO with [Pd(NO)]. The coordinative adsorption mechanisms resulted in the higher Pd(II) adsorption behaviors of R-IDA, R-Py, and R-BPA. HCl (5.0 M) and thiourea (0.1 M) eluents desorbed 83% of Pd(II) from R-IDA and 95% from R-Py, respectively. R-Py was the most effective Pd(II) adsorbent based on adsorption selectivity and desorption efficiency.

Cohesive/Adhesive strengths of CsOH-chemisorbed SS304 surfaces

Li, N.*; Sun, Y.*; Nakajima, Kunihisa; Kurosaki, Ken*

Journal of Nuclear Science and Technology, 11 Pages, 2023/00

https://doi.org/10.1080/00223131.2023.2231447

During the Fukushima Daiichi nuclear power plant (1F) accident, an overwhelming amount of the cesium remaining in the pressure vessel could have been deposited onto 304 stainless steel (SS304) steam separators and dryers, both with large surface areas. During 1F's decommissioning, the deposited cesium is a safety hazard as it can generate radioactive dust. However, the cohesive and adhesive strengths of CsOH-chemisorbed oxide scales are yet to be defined. In this study, we investigated how CsOH-chemisorption affects the cohesive and adhesive strengths between oxide scales and SS304 substrates with a scratch tester. The scratch test results revealed that the cohesive strengths of the oxide scales decreased after CsOH-chemisorption, while adhesive failure could not be reached.

On the adsorption and reactivity of element 114, flerovium

Yakushev, A.*; Lens, L.*; Dllmann, Ch. E.*; Khuyagbaatar, J.*; Jger, E.*; Krier, J.*; Runke, J.*; Albers, H. M.*; Asai, Masato; Block, M.*; et al.

Frontiers in Chemistry (Internet), 10, p.976635_1 - 976635_11, 2022/08

https://doi.org/10.3389/fchem.2022.976635

Flerovium (Fl, element 114) is the heaviest element chemically studied so far. The first chemical experiment on Fl suggested that Fl is a noble-gas-like element, while the second studies suggested that Fl has a volatile-metal-like character. To obtain more reliable conclusion, we performed further experimental studies on Fl adsorption behavior on Si oxide and gold surfaces. The present results suggest that Fl is highly volatile and less reactive than the volatile metal, Hg, but has higher reactivity than the noble gas, Rn.

Analytical studies of three-dimensional evaluation of radionuclide distribution in zeolite wastes through gamma scanning of adsorption vessels

Matsumura, Taichi; Nagaishi, Ryuji; Katakura, Junichi*; Suzuki, Masahide*

Nuclear Science and Engineering, 192(1), p.70 - 79, 2018/10

https://doi.org/10.1080/00295639.2018.1493856

The gamma-scanning of SDS (submerged demineralizer system) vessel used as a typical vessel for decontamination of radioactive water at Three Mile Island Unit 2 (TMI-2) accident was simulated in the axial and radial directions of real and cylindrical-shaped vessels by using a Monte Carlo calculation code (PHITS) on the basis of the geometrical and compositional information of vessel and gamma-scanning available in the previous reports at the accident. In the axial simulation, the true distribution of radioactive Cs in the zeolite packed bed of vessel was successfully evaluated when a correction function derived from a virtual constant distribution of Cs was applied to the reported gamma-scanning profile. In the radial simulation, the virtual disk-formed and shell-formed sources of Cs displaced in the packed bed were clearly observed from the top and bottom views of vessel. This new radial gamma-scanning indicates that the radial localization of Cs could be well observed by measuring gamma-ray from the top view of vessel during storage. We further examined the radial gamma-scanning from the side view whether the radial localization of Cs can be confirmed in the normally existing gamma-scanning room or not.

Minor actinides recovery from irradiated fuel for SmART cycle test

Takeuchi, Masayuki; Sano, Yuichi; Watanabe, So; Nakahara, Masaumi; Aihara, Haruka; Kofuji, Hirohide; Koizumi, Tsutomu; Mizuno, Tomoyasu

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 6 Pages, 2017/04

Diffusion and adsorption of uranyl ion in clays; Molecular dynamics study

Arima, Tatsumi*; Idemitsu, Kazuya*; Inagaki, Yaohiro*; Kawamura, Katsuyuki*; Tachi, Yukio; Yotsuji, Kenji

Progress in Nuclear Energy, 92, p.286 - 297, 2016/09

https://doi.org/10.1016/j.pnucene.2016.03.006

Diffusion and adsorption behavior of uranyl (UO) species is important for the performance assessment of radioactive waste disposal. The diffusion behaviors of UO, K, CO and Cl and HO in the aqueous solutions were evaluated by molecular dynamics (MD) calculations. The diffusion coefficient (De) of UO is the smallest and is 26% less than the self-diffusion coefficient of HO. For the aqueous solution with high concentration of carbonate ions, uranyl carbonate complexes: UOCO and UO(CO) can be observed. For the clay (montmorillonite or illite)-aqueous solution systems, the adsorption and diffusion behaviors of UO and K were evaluated by MD calculations. The distribution coefficients (Kd) increase with the layer charge of clay, and Kd of UO might be smaller than that of K. Further, their two-dimensional diffusion coefficients were relatively small in the adsorption layer and were extremely small for illite with higher layer charge.

Vacuum chromatography of Tl on SiO at the single-atom level

Steinegger, P.*; Asai, Masato; Dressler, R.*; Eichler, R.*; Kaneya, Yusuke*; Mitsukai, Akina*; Nagame, Yuichiro; Piguet, D.*; Sato, Tetsuya; Schdel, M.; et al.

Journal of Physical Chemistry C, 120(13), p.7122 - 7132, 2016/04

https://doi.org/10.1021/acs.jpcc.5b12033

A new experimental method "vacuum chromatography" has been developed to measure adsorption enthalpy of superheavy elements, and its feasibility has been examined using short-lived thallium isotopes. The short-lived thallium isotopes were produced at the JAEA tandem accelerator. The thallium ion beam prepared with an on-line isotope separator which ionized and mass-separated the thallium isotopes was injected into an isothermal vacuum chromatography apparatus. A temperature-dependent adsorption property of thallium atom on SiO surface were measured. The adsorption enthalpy of thallium was determined to be 158 kJ/mol. The thallium is a homolog of element 113. Thus, the vacuum chromatography developed in this study enables us to perform chemical experiments for short-lived superheavy elements with half-lives of a order of one second.

Degradation of 2-chlorophenol by -ray irradiation in zeolite/water mixtures

Kumagai, Yuta

Hoshasen Kagaku (Internet), (99), p.53 - 56, 2015/04

Radiation-induced degradation of 2-chlorophenol (2-ClPh) in zeolite/water mixtures was studied in order to consider a possibility of adsorption on zeolites to improve efficiencies of irradiation treatments of water contaminated by organic compounds. The degradation of 2-ClPh by -ray irradiation was investigated as a model compound. The degradation was evaluated by chloride ion (Cl) production. A high concentration of Cl was observed after the irradiation of a mixture with a mordenite-type zeolite (NaMOR), whereas A-type and X-type zeolites showed no significant effect. Therefore, for the mixture with NaMOR, effects of pH of the solution and of the 2-ClPh concentration were examined. At pH 5.7, the excess production of Cl was induced by the addition of NaMOR. Concurrently, adsorption of 2-ClPh on NaMOR was observed. When the mixture contained a higher concentration of 2-ClPh at pH 5.7, the Cl production increased. The adsorption of 2-ClPh also increased with increasing concentration. The results suggest that organics adsorbed on zeolites are decomposed by irradiation effectively at high adsorption concentrations.

Cesium-adsorption behavior of weathered biotite from Fukushima Prefecture depends on the degree of vermiculitization

Yamada, Hirohisa*; Yokoyama, Shingo*; Watanabe, Yujiro*; Suzuki, Masaya*; Suzuki, Shinichi; Hatta, Tamao*

Nihon Ion Kokan Gakkai-Shi, 25(4), p.207 - 211, 2014/11

http://doi.org/10.5182/jaie.25.207

Research and development on partitioning in JAERI; Review of the research activities until the development of 4-group partitioning process

Morita, Yasuji; Kubota, Masumitsu*

JAERI-Review 2005-041, 35 Pages, 2005/09

JAERI-Review-2005-041.pdf:2.24MB

Research and development on Partitioning in JAERI are reviewed in the present report from the beginning to the development of the 4-Group Partitioning Process and its test with real high-level liquid waste (HLLW). In the 3-Group Partitioning Process established in around 1980, elements in HLLW are separated into 3 groups of transuranium element group, Sr-Cs group and the other element group. The 4-Group Partitioning Process subsequently developed contains the separation of Tc-platinum group metals additionally. The process was tested to demonstrate its performance with real concentrated HLLW. Until then, various separation methods for various elements were studied and selection and optimization of the separation methods were carried out to establish the process. Review of the experience, findings and results is very important and valuable for future study on partitioning. The present report is prepared from this point of view.