• Journal of environmental and Sanitary engineering
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• v.19 no.4 s.54
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• pp.1-8
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• 2004

This study has been investigated to analyze the thermal stability of cesium reacted with fly ash with changing mole ratio of Cs/Al in hydrogen atmosphere. When the $CsNO_3$ and fly ash were reacted at $1000^{\circ}C$ in hydrogen atmosphere, cesium $nepheline(CsAlSiO_4)$ Phase began to emerge in addition to $pollucite(CsAlSi_2O_6)$ phase when the cesium loading quantity was greater than $0.32(g-Cs_2O/g-fly\; ash)$. Cesium $nepheline(CsAlSiO_4)$ Phase increased with increasing cesium loading quantity. When cesium trapped on a fly ash was exposed to $1200^{\circ}C$ in hydrogen atmosphere, no weight loss due to the volatilization was shown until the cesium loading quantity was reached at $0.32(g-Cs_2O/g-fly\; ash)$. In the case of the cesium loading quantity of $0.48-0.74(g-Cs_2O/g-fly\;ash)$ in hydrogen atmosphere, the weight loss increased with increasing the cesium loading quantity. This is considered to be due to the cesium $nepheline(CsAlSiO_4)$ whose vapor pressure is higher than that of $pollucite(CsAlSi_2O_6)$.

• Korean Journal of Mineralogy and Petrology
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• v.36 no.4
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• pp.313-321
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• 2023

Numerous studies have investigated the adsorptive sequestration of radioactive cesium in the natural environment. Among these studies, adsorption onto minerals and high-temperature treatment stand out as highly effective, as demonstrated by the use of zeolite. In this study, cesium was ion-exchanged with birnessite and subsequently underwent high-temperature treatment up to 1100℃ to investigate both mineral phase transformation and the leaching characteristics of cesium. Birnessite has a layered structure consisting of MnO₆ octahedrons that share edges, demonstrating excellent cation adsorption capacity. The high-temperature treatment of cesium-ion-exchanged birnessite resulted in changes in the mineral phase, progressing from cryptomelane, bixbyite, birnessite to hausmannite as the temperature increased. This differs from the phase transformation observed in the tunneled manganese oxide mineral todorokite ion-exchanged with cesium, which shows phase transformation only to birnessite and hausmannite. The leaching of cesium from cesium-ion-exchanged birnessite was estimated by varying the reaction time using both distilled water and a 1 M NaCl solution. The leaching quantity changed according to the treatment temperature, reaction time, and type of reaction solution. Specifically, the cesium leaching was higher in the sample reacted with 1 M NaCl compared to the sample with distilled water and also increased with longer reaction time. For the samples reacted with distilled water, the cesium leaching initially increased and then decreased, while in the NaCl solution, the leaching decreased, increased again, and finally nearly stopped like the sample in the distilled water for the sample treated at 1100℃. These changes in leaching are closely associated with the mineral phases formed at different temperatures. The phase transformation to cryptomelane and birnessite enhanced cesium leaching, whereas bixbyite and hausmannite hindered leaching. Notably, hausmannite, the most stable phase occurring at the highest temperature, demonstrated the greatest ability to inhibit cesium leaching. This results strongly suggest that high-temperature treatment of cesium-ion-exchanged birnessite effectively immobilizes and sequesters cesium.

• Nuclear Engineering and Technology
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• v.5 no.4
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• pp.310-320
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• 1973

The sorption and fixation of cesium in dilute solutions by vermiculite saturated with Na or K were studied in order to investigate any possibibty of its use in radioactive effluent treatment. The cesium sorbed by vermiculite with the increase in pH is attributed to the increase of sorption surface as a result of the dispersion. The increased cesium sorption by Na-vermiculite is due to the different sorption rates by the different exchange sites : external surface and internal surface. It is shown that the larger amount of sorbed cesium was extracted by KCI rather than with any other extractants. It is suggested that the fixation of cesium by vermiculite occurs at the crystal edge where Cs may replace K. Domestic vermiculite is a valuable material for use in the cesium sorption and fixation, and might be useful as a good packing material outside the tank of highly radioactive liquid waste. And from these results one could suggest that the artificial alteration of the biotite to vermiculite might be occurring by treating with NaCl.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.516-522
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• 2023

The co-precipitation process plays a key role in the decontamination of radionuclides from low and intermediate levels of liquid waste. For that reason, the removal of Cs ions from waste solution by the co-precipitation method was carried out. A simulated liquid waste (¹³³Cs) was prepared from a 0.1 M CsCl solution, while wastewater generated by washing steel ash served as a representative of radioactive cesium solution (¹³⁷Cs). By co-precipitation, potassium ferrocyanide was applied for the adsorption of Cs ions, while nickel nitrate and iron sulfate were selected for supporting the precipitation. The amount of residual Cs ions in the CsCl solution after precipitation and filtration was determined by ICP-OES, while the radioactivity of ¹³⁷Cs was measured using a gamma-ray spectrometer. After cesium removal, the amount of cesium appearing in both XRD and SEM-EDS was analyzed. The removal efficiency of ¹³³Cs was 60.21% and 51.86% for nickel nitrate and iron sulfate, respectively. For the ash-washing solution, the removal efficiency of ¹³⁷Cs was revealed to be more than 99.91% by both chemical agents. This implied that the co-precipitation process is an excellent strategy for the effective removal of radioactive cesium in waste solution treatment.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.3017-3026
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• 2022

The ¹³¹Cs radioisotope with a short half-life time and high average radiation energy can treat the cancer effectively in prostate brachytherapy. The typical ¹³¹Cs production processes have a separation step of the cesium from ¹³¹Ba to obtain a high specific radioactivity. Herein, we suggested a novel ¹³¹Cs separation method based on the Ba²⁺ adsorption of alginate beads. It is necessary to reduce the affinity of alginate beads to cesium ions for a high production yield. The carboxyl group of the alginate beads was replaced by a sulfonate group to reduce the cesium affinity while reinforcing their affinity to barium ions. The modified beads exhibited superior Ba²⁺ adsorption performances to native beads. In the fixed-bed column tests, the saturation time and adsorption capacity could be estimated with the Yoon-Nelson model in various injection flow rates and initial concentrations. In terms of the Cs elution, the modified alginate showed better performance (i.e., an elution over 88%) than the native alginate (i.e., an elution below 10%), indicating that the functional group modification was effective in reducing the affinity to cesium ions. Therefore, the separation of cesium from the barium using the modified alginate is expected to be an additional option to produce ¹³¹Cs.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.5
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• pp.549-554
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• 2014

This study was evaluated the applicability of the membrane filtration process (Micro Filtration (MF), nanofiltration membranes (NF), reverse osmosis (RO)) on the major radioactive substances, iodine ($I^-$) and cesium ($Cs^+$) using membranes produced in Korea and domestic raw water. Iodine ($I^-$) or cesium ($Cs^+$) in the microfiltration membrane (MF) process could not be expected removal efficiency by eliminating marginally at the combined state with colloidal and turbidity material. At the domestic raw water (lake water, turbidity 1.2 NTU, DOC 1.3 mg/L) conditions, nanofiltration membrane (NF) and reverse osmosis (RO) showed a high removal rate of about 88 ~ 99% for iodine ($I^-$) and cesium ($Cs^+$) and likely to be an alternative process for the removal of radioactive material.

• Journal of the Korean Magnetics Society
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• v.4 no.2
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• pp.184-187
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• 1994

Nuclear magnetic resonance of $^{133}Cs$ in a $CsMnCl_{3}$ single crystal grown by the Czochralski method has been investigated by employing a Bruker FT NMR spectrometer. The $^{133}Cs$ resonance of two different groups were recorded. Various transitions belonging to two cesium spectra of a different intensity ratio are analyzed. The quadrupole coupling constant of Cs(I) is $0.15{\pm}0.01$ MHz, and that of Cs(II) is $0.21{\pm}0.01$ MHz. The anisotropy parameter is zero for both. The principal axes of the EFG tensors for these two sites are found to be the same. The Z axis, conventionally the largest component of the EFG tensor, is parallel to the crystallographic c-axis.

• Journal of Radiation Protection and Research
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• v.3 no.1
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• pp.1-5
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• 1978

Investigation is carried out that low-level liquid radioactive wastes which is consisted of long half-life nuclides such as cesium can be treated by Korean clinoptillolite as a kind of zeolites. Column operation using a activated clinoptillolite shows good results in terms of break-through curves and comparing to clinoptillolite classified at WARD in U.S, Korean clinoptillolite shows a tailing phenomena longer than that of WARD. The fixation quantity of radioactivity in Korea clinoptillolite is to be about $75{\mu}Ci/100g$ using a $2.5{\times}10^{-3}{\mu}Ci/ml$ solution.

• Journal of the Korean institute of surface engineering
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• v.51 no.5
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• pp.257-262
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• 2018

Cesium lead halide perovskite quantum dots (QDs) have recently emerged as highly promising opto-electronic materials. Despite the relative facile anion exchange reactions in cesium lead halide perovskite QDs, in depth study of the anion exchange reactions such as reaction kinetics are required that can provide insight into the crystal transformation in the cesium lead halide perovskite QDs. Herein, we investigated the anion exchange reaction from $CsPbI_3$ QDs to $CsPbBr_3$ QDs with varying the particle size of the starting $CsPbI_3$ QDs. By characterizing the PL spectra in the anion exchange reaction process, we observed that discontinuous PL peak shifts during I-to-Br anion exchange reaction in starting $CsPbI_3$ QDs over a critical size. Origin of the discontinuous I-to-Br anion exchange kinetics are mainly due to thermodynamically unstable nature of the $CsPb(Br/I)_3$ alloy QDs.

• Korean Journal of Environmental Agriculture
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• v.2 no.1
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• pp.30-34
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• 1983

The present study was carried out to determine the effect of a radionuclide, cesium-137, in soybean, which is an element released usually from nuclear facilities. Soybean plants were grown on the pots treated with cesium-137 $0.5{\sim}60{\mu}Ci/1kg$ soil and the uptake, translocation and accumulation of the radiocesium in the plant parts were measured at different growth stage. The results are summarized as follows: 1) Visual toxic symptoms on the plants due to treatment of radioactive cesium were not observed up to $60{\mu}Ci/10Kg$ soil in a pot. 2) The uptake of cesium-137 in soybean plant was increased with increment of concentration applied, while the uptake of potassium was proportionally decreased, indicating to have an ion antagonistic relationship between them. 3) The absolute amounts of cesium-137 in the plants were gradually increased by the pod setting stage, but rather reduced at harvesting stage. The accumulation occurred more in the leaves and stems than the soybean seeds. 4) The rate of uptake was ranged from 0.069 to 0.005 with proportional decrease by increasing concentration applied and the rate of Cs-137 translocation from plants to seeds was averaged 38.6% in soybean plant. The concentration coefficient was 0.04 in the soybean seeds from the pots treated with $20{\mu}Ci$ of cesium-137 and decreased with increment of cesium-137 applied.