• Title/Summary/Keyword: Chemical Decontamination

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Effects of Decontamination Treatments on Chemical Components of Panax Ginseng-Leaf Tea (살균처리가 인삼엽록차의 화학성분에 미치는 영향)

  • Kwon, Joong-Ho;Byun, Myung-Woo;Choi, Kang-Ju;Kwon, Dae-Won;Cho, Han-Ok
    • Korean Journal of Food Science and Technology
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    • v.24 no.1
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    • pp.65-69
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    • 1992
  • The comparative effects of ethylene oxide(EO) fumigation and gamma irradiation (5 kGy) were determined on the chemical components of exportable ginseng-leaf tea which is required for improving the hygienic quality. Saponins and fatty acids detected in the samples were found to be resistant to both treatments at the practical levels. In an experiment on free sugar and amino acids, however, quantitative analysis has shown that glucose, lysine and histidine in the samples are significantly decreased by EO fumigation (p<0.05) and that negligible changes were observed in gamma-irradiated samples.

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Electrosorption of U(IV) by Electochemically Modified Activated Carbon Fibers

  • Jung, Chong-Hun;Oh, Won-Zin;Lee, Yu-Ri;Park, Soo-Jin
    • Carbon letters
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    • v.6 no.1
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    • pp.25-30
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    • 2005
  • The electrosorption of U(VI) from waste water was carried out by using an activated carbon fiber (ACF) felt electrode in a continuous electrosorption cell. In order to enhance the electrosorption capacity at a lower potential, the ACF was electrochemically modified in an acidic and a basic solution. Pore structure and functional groups of the electrochemically modified ACF were examined, and the effects of the modification conditions were studied for the adsorption of U(VI). Specific surface area of all the ACFs was decreased by this modification. The amount of the acidic functional groups decreased with a basic modification, while the amount increased a lot with an acidic modification. The electrosorption capacity of U(VI) decreased on the acid modified electrode due to the shielding effect of the acidic functional groups. The base modified electrode enhanced the capacity due to a reduction of the acidic functional groups. The electrosorption amount of U(VI) on the base modified electrode at .0.3 V corresponds to that of the as-received ACF electrode at .0.9 V. Such a good adsorption capacity was due to a reduction of the shielding effect and an increase of the hydroxyl ions in the electric double layer on the ACF surface by the application of negative potential.

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The Purification of Decontamination Liquid Waste by Electrosorption (전기적 흡 . 탕착에 의한 제염폐액의 정화처리기술)

  • 정종헌;문제권;김규남;이성호;이상문
    • Resources Recycling
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    • v.8 no.3
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    • pp.18-25
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    • 1999
  • The study on the electrosorption of cobalt ions onto a porous activated carbon fiber (ACF) was performed to treat radioactive liquid wastes resulting from chemical or electrochemical decontamination and to regenerate the spent carbon electrode, Cyclic voltammetry was investigated on a rotating-disk electrode (RDE) to determine the region of potentials within which only double-layer charging should occur. The application of an electric potential increased the sorption of the cobalt ions. The adsorbed cobalt Ions could be released into the solution by reversing the appling potential, showing the reversibility of the process.

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Evaluation of decontamination factor of radioactive methyl iodide on activated carbons at high humid conditions

  • Choi, Byung-Seon;Kim, Seon-Byeong;Moon, Jeikwon;Seo, Bum-Kyung
    • Nuclear Engineering and Technology
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    • v.53 no.5
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    • pp.1519-1523
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    • 2021
  • Radioactive iodine (131I) released from nuclear power plants has been a critical environmental concern for workers. The effective trapping of radioactive iodine isotopes from the off-gas stream generated from nuclear facilities is an important issue in radioactive waste treatment systems evaluation. Numerous studies on retaining methyl iodide (CH3I131) by impregnated activated carbons under the high content of moisture have been extensively studied so far. But there have been no good results on how to remove methyl iodide at high humid conditions up to now. A new challenge is to introduce other promising impregnating chemical agents that are able to uptake enough radioactive methyl iodide under high humid conditions. In order to develop a good removal efficiency to control radioiodine gas generated from a high humid process, activated carbons (ACs) impregnated with triethylene diamine (TEDA) and qinuclidine (QUID) were prepared. In addition, the removal efficiencies of the activated carbons (ACs) under humid conditions up to 95% RH were evaluated by applying the standard method specified in ASTM-D3808. Quinuclidine impregnated activated carbon showed a much higher decontamination factor above 1,000, which is enough to meet the regulation index for the iodine filters in nuclear power plants (NPPs).