Cs desorption behavior during hydrothermal treatment of illite with oxalic acid

Kim, Sung-Man; Yoon, In-Ho; Kim, Ilgook; Park, Chan Woo; Sihn, Youngho; Kim, June-Hyun; Park, So-Jin

doi:10.1007/s11356-020-09675-3

Cited by 11 publications

(3 citation statements)

References 39 publications

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“…In this study, we focused on oxalic acid which has relatively high desorption efficiency in previous thermal treatment without a special experimental environment (Kim et al 2020). The potential of oxalic acid was evaluated by the desorption experiment of Cs + from model contaminated biotite without heating.…”

Section: Introductionmentioning

confidence: 99%

Extraction of Cs bound with biotite by addition of oxalic acid without heating

et al. 2022

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There is a large quantity of contaminated soil with radionuclides due to the accident of Fukushima Daiichi Nuclear Power Plant in Japan. Some previous studies reported that Cs + could be desorbed from soil with high efficiency, however, these methods required huge input energy for operating. Therefore, we focused on oxalic acid, which has shown relatively high desorption efficiency in previous thermal treatment, and evaluated the potential of oxalic acid as a leaching reagent to reduce the volume of contaminated soil without heating. MethodsStable isotope Cs + contaminated biotite was retained in plastic bag for 3 months for aging. Oxalic acid was added to the contaminated biotite and the mixture was maintained around 20 °C. After each leaching time, the mixture was separated using filter paper and the concentration of Cs + in filtrate was measured. Structural changes in biotite before and after leaching were also analyzed. LiNO3 was also used for comparison studies. ResultsThe desorption efficiency of Cs + from biotite by leaching with oxalic acid was 94.9% after 2 weeks and the intensity of the specific reflection for biotite in the X-ray diffractograms decreased with leaching time.These results indicate that oxalic acid can remove Cs + from biotite through the decomposition of the biotite structure. Since LiNO3 desorbed only 32.2% of Cs + as ion-exchangeable form after 2 weeks, oxalic acid can desorb Cs + , which has a strong interaction with biotite such as the inner-sphere complex, without heating. ConclusionAlthough the desorption of Cs + from biotite by leaching with oxalic acid leaching takes a long time, it is a great advantage that this leaching method does not require external energy such as heating. Therefore, oxalic acid leaching has high potential to reduce the volume of contaminated soil with radionuclides.

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Section: Introductionmentioning

confidence: 99%

Extraction of Cs bound with biotite by addition of oxalic acid without heating

et al. 2022

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“…7 In our recent studies, we achieved over 90% 137 Cs desorption in hydrobiotite, which is an expandable clay, using acid treatment under hydrothermal conditions, whereas we achieved ∼69% 137 Cs desorption in illite under identical experimental conditions. 8,9 Therefore, to increase the decontamination efficiency of actual contaminated soil composed of various clay minerals, a highly efficient technique should be developed for Cs removal from illite clay. Heat treatment that results in significant Cs removal by forming volatile species is an efficient decontamination approach.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Since Cs + ions are highly soluble in water and behave similar to group I cations (e.g., K + ions) in living organisms, their intake is likely fatal . It is well understood that Cs + ions have a strong affinity for clay minerals in soil; − thus, exposed Cs is expected to be incorporated into the soil. Vast amounts of soil have been contaminated by 137 Cs owing to nuclear power plant accidents at the Chernobyl and Fukushima Daiichi sites. − Plants grown in the contaminated soil may absorb 137 Cs and be consumed by humans, leading to critical health problems.…”

Section: Introductionmentioning

confidence: 99%

Cesium Removal from Nonexpandable Illite Clay by Chloride Salt Treatment

Kim

Jeon

et al. 2021

ACS Omega

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Extracting cesium (Cs) from nonexpandable illite clay is important in the remediation of radioactive Cs-contaminated soil. In this study, we investigated a chloride salt treatment technique for the removal of Cs from illite. Cs-loaded illite samples with initial Cs concentrations of 2430 and 690 ppm were treated using a NaCl−MgCl 2 −CaCl 2 ternary salt system at 400−850 °C under ambient pressure to suppress Cs loss by vaporization. As a result of the treatment at 850 °C, wherein the salt was in a molten state, the Cs concentration was reduced by 99.5% (to 11.6 ppm) in the first sample and by 99.4% (to 3.86 ppm) in the second sample. Cs removal was achieved for these two samples even in a solid-state reaction at 400 °C, with reductions of 83.3% (407 ppm) and 73.3% (184 ppm), respectively. CsCl was formed by the reaction and remained stable in the salt. The incorporation of cations from the salt (mainly Mg 2+ ) to illite induced structural evolution forming an indialite phase to expel Cs from the clay samples.

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