• Journal of Korean Society of Water and Wastewater
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• v.32 no.5
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• pp.399-409
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• 2018

Prussian blue is known as a superior material for selective adsorption of radioactive cesium ions; however, the separation of Prussian blue from aqueous suspension, due to particle size of around several tens of nanometers, is a hurdle that must be overcome. Therefore, this study aims to develop granule type adsorbent material containing Prussian blue in order to selectively adsorb and remove radioactive cesium in water. The surface of granular activated carbon was grafted using a covalent organic polymer (COP-19) in order to enhance Prussian blue immobilization. To maximize the degree of immobilization and minimize subsequent detachment of Prussian blue, several immobilization pathways were evaluated. As a result, the highest cesium adsorption performance was achieved when Prussian blue was synthesized in-situ without solid-liquid separation step during synthesis. The sample obtained under optimal conditions was further analyzed by scanning electron microscope-energy dispersive spectrometry, and it was confirmed that Prussian blue, which is about 9.7% of the total weight, was fixed on the surface of the activated carbon; this level of fixing represented a two-fold improvement compared to before COP-19 modification. In addition, an elution test was carried out to evaluate the stability of Prussian blue. Leaching of Prussian blue and cesium decreased by 1/2 and 1/3, respectively, compared to those levels before modification, showing increased stability due to COP-19 grafting. The Prussian blue based adsorbent material developed in this study is expected to be useful as a decontamination material to mitigate the release of radioactive materials.

• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2289-2294
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• 2021

In the present study, an original spark plasma sintering-reactive synthesis (SPS-RS) method for minerallike ceramic materials based on SrAl₂Si₂O₈ feldspar-like skeleton structure was used for the first time, promising solid-state matrices for reliable immobilization of high-energy ⁹⁰Sr. The method is based on the "in-situ" reaction of a mixture of SrO, Al₂O₃ and SiO₂ oxides when heated by a unipolar pulsed current under compacting pressure. The phase and elemental composition structure were studied. The dynamics of the consolidation of the reaction mixture of oxides was studied in the range of 900-1200 ℃. The study found the temperature of the high-speed (minutes) SPS-RS formation of single-phase SrAl₂Si₂O₈ composition ceramic in the absence of intermediate reaction products with a relative density of up to 99.2% and compressive strength up to 145 MPa and a strontium leaching rate of 10^-4g/cm²·day.

• Korean Journal of Environmental Agriculture
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• v.37 no.3
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• pp.179-188
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• 2018

BACKGROUND: Reclamation of heavy metal-contaminated agricultural fields has intensively been done to ensure the soil quality and food security. This study evaluated the efficiency and longevity of current physical and chemical approaches for heavy metal-contaminated soils. METHODS AND RESULTS: Concentrations of 0.1 N HCl-leachable trace metals of Cd, Pb, and As from the stabilizing agents-treated soils decreased by 50%, 70%, and 40%, respectively, compared to the control. Among the stabilizing agents, the $CaCO_3$ was the best for stabilization. For physical stabilization, the soil dressing reduced the concentrations of Cd, Pb, and As by 88%, 94%,and 88%, respectively, compared to the control. Moreover, the dilution of the contaminated soils decreased the metals by an average of 25.3% when compared with the control. The longevity of each stabilization method was determined by using the availability assessment of heavy metals in the soils. Results showed that the leaching methods using HCl and $NH_4NO_3$ had 120 and 32 weeks longevity, respectively. Interestingly, any stabilization efficacy was not found over the time for Cd and Pb (i.e., cation metals), whereas the stabilization efficacy of As was sharply decreased under 50% after 32 weeks. However, the change of metal concentration was not significant with the physical stabilization compared to the chemical stabilization. CONCLUSION: The stabilization methods should carefully be selected based on long-term monitoring under climate conditions.

• Economic and Environmental Geology
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• v.37 no.1
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• pp.107-111
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• 2004

This study was undertaken to summarize of the efficiencies of the passive treatment system and suggest future studies for the solution of mine drainage problem. Flow rates of mine drainage from the abandoned coal mines are about 80,000 ton/day. Contaminated mine drainages over about 50 ton/day of flow rate were treated by passive treatment facilities such as Successive Alkalinity Producing Systems(SAPS), oxidation pond and oxic wetland. Chemical analysis for 13 passive coal mine treatment facilities showed that SAPS was the core of treatment facilities because the variation of Fe removal rates was relatively smaller than any other processes and re-leaching of Fe was not measured. The performance and life of SAPS depended on decrease in permeability and retention time due to accumulation of sludge. It is inferred that upgrade of design of the passive treatment system and in-situ treatment using underground void will be necessary for the amelioration of the mine drainage with high metal loading rates.