• Title/Summary/Keyword: complexation

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Characterization of the Purified Ca-type Bentonil-WRK Montmorillonite and Its Sorption Thermodynamics With Cs(I) and Sr(II)

  • Seonggyu Choi;Bong-Ju Kim;Surin Seo;Jae-Kwang Lee;Jang-Soon Kwon
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.21 no.4
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    • pp.427-438
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    • 2023

  • Thermodynamic sorption modeling can enhance confidence in assessing and demonstrating the radionuclide sorption phenomena onto various mineral adsorbents. In this work, Ca-montmorillonite was successfully purified from Bentonil-WRK bentonite by performing the sequential physical and chemical treatments, and its geochemical properties were characterized using X-ray diffraction, Brunauer-Emmett-Teller analysis, cesium-saturation method, and controlled continuous acid-base titration. Further, batch experiments were conducted to evaluate the adsorption properties of Cs(I) and Sr(II) onto the homoionic Ca-montmorillonite under ambient conditions, and the diffuse double layer model-based inverse analysis of sorption data was performed to establish the relevant surface reaction models and obtain corresponding thermodynamic constants. Two types of surface reactions were identified as responsible for the sorption of Cs(I) and Sr(II) onto Ca-montmorillonite: cation exchange at interlayer site and complexation with edge silanol functionality. The thermodynamic sorption modeling provides acceptable representations of the experimental data, and the species distributions calculated using the resulting reaction constants accounts for the predominance of cation exchange mechanism of Cs(I) and Sr(II) under the ambient aqueous conditions. The surface complexation of cationic fission products with silanol group slightly facilitates their sorption at pH > 8.

  • https://doi.org/10.7733/jnfcwt.2023.033 인용 PDF

Stabilization of Polyphenolic Antioxidants Using Inclusion Complexation with Cyclodextrin and Their Utilization as the Fresh-food Preservative (폴리페놀계 천연 항산화제의 cyclodextrin inclusion complexation을 통한 안정화와 식품 보존제로의 활용)

  • Kim, Tae-Kwon;Shin, Hyun-Dong;Lee, Yong-Hyun
    • Korean Journal of Food Science and Technology
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    • v.35 no.2
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    • pp.266-271
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    • 2003

  • Insoluble polyphenol antioxidants, quercetin and catechin, were stabilized through the complexation with cyclodextrin to increase heat and pH stabilities. Comparison of inclusion complex formabilities of quercetin and catechin with ${\alpha}-,\;{\beta}-$, and ${\gamma}-CDs$ revealed ${\beta}-CD$ to be the most suitable result. Optimal molar mixing ratio of ${\beta}-CD$ and quercetin or catechin for inclusion complex formation was found to be 1 : 1. Inclusion complexation was confirmed using differential scanning calorimetry. Solubility of ${\beta}-CD-antioxidant$ inclusion complexes increased compared with native antioxidants, Stability against temperature and pH of ${\beta}-CD-antioxidant$ inclusion complex analyzed revealed antioxidant activities of ${\beta}-CD-quercetin$ and catechin inclusion complexes have higher stabilization compare to raw quercetin and catechin. Peroxide value of linoleic acid dissolved in water decreased substantionally after using ${\beta}-CD-quercetin$ inclusion complex. ${\beta}-CD-antioxidant$ inclusion complex can be used effectively as a fresh-food preservative.

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