• Title, Summary, Keyword: Green rust

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Aqueous U(VI) removal by green rust and vivianite at phosphate-rich environment

  • Sihn, Youngho;Yoon, In-Ho
    • Membrane Water Treatment
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    • v.11 no.3
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    • pp.207-215
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    • 2020
  • Vivianite (Fe32+(PO4)2·8H2O) and green rust ([Fe42+Fe23+(OH)-12][SO42-·2H2O]2-), ferrous containing minerals, could remove aqueous U(VI) in 5 min. and the efficiencies of green rust were roughly 2 times higher than that of vivianite. The zeta potential measurement results implies that the better performance of green rust might be attributed to the favorable surface charge toward uranyl phosphate species. The removal behaviors of the minerals were well fitted by pseudo-second order kinetic model (R2 > 0.990) indicating the dominant removal process was chemical adsorption. Effects of Ca2+ and CO32- at pH 7 were examined in terms of removal kinetic and capacity. The kinetic constants of aqueous U(VI) were 8 and 13 times lower (0.492 × 10-3 g/(mg·min); 0.305 × 10-3 g/(mg·min)) compared to the value in the absence of the ions. The thermodynamic equilibrium calculation showed that the stable uranyl species (uranyl tri-carbonate) were newly formed at the condition. Surface investigation on the reacted mineral with uranyl phosphates species were carried out by XPS. Ferrous iron and U(VI) on the green rust surface were completely oxidized and reduced into Fe(III) and U(IV) after 7 d. It suggests that the ferrous minerals can retard U(VI) migration in phosphate-rich groundwater through the adsorption and subsequent reduction processes.

Sorption of I and Se onto Green Rusts with Different Interlayer Anions, GR(CO32-) AND GR(Cl-)

  • Min, J.H.;Baik, M.H.;Lee, J.K.;Jeong, J.T.
    • Journal of Nuclear Fuel Cycle and Waste Technology
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    • v.1 no.1
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    • pp.57-63
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    • 2013
  • Natural green rust (GR) can retard the migration of anions through geological media because it has a Layer Double Hydroxyl (LDH) structure with a positive charge. In this study, the sorption behaviors of anions such as selenite ($Se(IV)O{_3}^{2-}$), selenate ($Se(VI)O{_4}^{2-}$), and iodide ($I^-$) onto green rusts with different structures, i.e., GR($Cl^-$) and GR($CO{_3}^{2-}$), were investigated by conducting batch sorption experiments in an anoxic condition. Experimental results showed that selenite was mostly sorbed onto GR($CO{_3}^{2-}$) and then partly reduced to metal selenium, Se(0). However, little selenate and iodide was sorbed onto GR($CO{_3}^{2-}$) while some iodide was sorbed onto GR($Cl^-$). It is presumed from the experimental results that the major sorption mechanism of $SeO{_3}^{2-}$ and $I^-$ onto green rusts is the anion exchange reaction with the anions existing in the interlayer of the rusts. Green rust, therefore, can play an important role in the retardation of anions migrating through deep geological environments owing to its LDH structure with a high anion exchange capacity.

Identification of Active Agents for Reductive Dechlorination in Cement/Fe(II) Systems (시멘트와 Fe(II)을 이용한 환원성 탈염소화반응의 유효반응성분 규명)

  • Kim, Hong-Seok;Lee, Yu-Jung;Kim, Ha-Yan;Hwang, In-Seong
    • Journal of Soil and Groundwater Environment
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    • v.11 no.6
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    • pp.35-42
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    • 2006
  • Experimental study was conducted to identify the active agent for reductive dechlorination of TCE in cement/Fe(II) systems. Several potential materials-hematite (${\alpha}-Fe_2O_3$), lepidocrocite (${\gamma}$-FeOOH), akaganeite (${\beta}$-FeOOH), ettringite ($Ca_6Al_2(SO_4)_3(OH)_{12}$)-that are cement components or parts of cement hydrates were tested if they could act as reducing agents by conducting TCE degradation experiments. From the initial degradation experiments, hematite was selected as a potential active agent. The pseudo-first-order degradation rate constant ($k\;=\;0.637\;day^{-1}$) for the system containing 200 mM Fe(II), hematite and CaO was close to that ($k\;=\;0.645\;day^{-1}$) obtained from the system containing cement and 200 mM Fe(II). CaO, which was originally added to simulate pH of the cement/Fe(II) system, was found to play an important role in degradation reactions. The reactivity of the hematite/CaO/Fe(II) system initially increased with increase of CaO dosage. However, the tendency declined in the higher CaO dosage region, implying a saturation type of behavior. The SEM analysis revealed that the hexagonal plane-shaped crystals were formed during the reaction with increasing degradation efficiency, which was brought about by increasing the CaO dosage. It was suspected that the crystals could be portlandite or green rust ($SO_4$) or Friedel's salt. The XRD analysis of the same sample identified the peaks of hematite, magnetite/maghemite, green rust ($SO_4$). Either instrumental analysis predicted the presence of the green rust ($SO_4$). Therefore, the green rust ($SO_4$) would potentially be a reactive agent for reductive dechlorination in cement/Fe(II) systems.

토양 중 mineral에 의한 염소계 유기화합물 분해 특성 연구

  • Choi Jeong-Yun;Sim Sang-Gyu;Lee U-Jin
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • pp.33-36
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    • 2006
  • The reductive dechlorination of chlorinated organic compounds by soil minerals in soil and groundwater were carried out in this study. FeS, green rust, and magnetite were chosen as the representative soil minerals which were capable of degrading chlorinated compound in soil system. FeS was the most effective reductant in degradation of carbon tetrachloride. The reductive degradation of CT and 1,1,1-TCA by FeS was much faster than that of 1,2-DCB and 2,4-DCP. The reactivity of FeS was effectively improved by the addition of trace metals. The addition of Co to FeS suspension enhanced the reaction rate of 1,2-DCB by a factor of 46 compared to that by FeS without Co.

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Insights into Tan Spot and Stem Rust Resistance and Susceptibility by Studying the Pre-Green Revolution Global Collection of Wheat

  • Abdullah, Sidrat;Sehgal, Sunish Kumar;Jin, Yue;Turnipseed, Brent;Ali, Shaukat
    • The Plant Pathology Journal
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    • v.33 no.2
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    • pp.125-132
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    • 2017
  • Tan spot (TS), caused by the fungus Pyrenophora tritici-repentis (Died) Drechs, is an important foliar disease of wheat and has become a threat to world wheat production since the 1970s. In this study a globally diverse pre-1940s collection of 247 wheat genotypes was evaluated against Ptr ToxA, P. tritici-repentis race 1, and stem rust to determine if; (i) acquisition of Ptr ToxA by the P. tritici-repentis from Stagonospora nodorum led to increased pathogen virulence or (ii) incorporation of TS susceptibility during development stem rust resistant cultivars led to an increase in TS epidemics globally. Most genotypes were susceptible to stem rust; however, a range of reactions to TS and Ptr ToxA were observed. Four combinations of diseasetoxin reactions were observed among the genotypes; TS susceptible-Ptr ToxA sensitive, TS susceptible-Ptr ToxA insensitive, TS resistant-Ptr ToxA insensitive, and TS resistant-Ptr ToxA toxin sensitive. A weak correlation (r = 0.14 for bread wheat and -0.082 for durum) was observed between stem rust susceptibility and TS resistance. Even though there were no reported epidemics in the pre-1940s, TS sensitive genotypes were widely grown in that period, suggesting that Ptr ToxA may not be an important factor responsible for enhanced prevalence of TS.

Comparative Study of Ni effect on the Corrosion Behavior of Low Alloy Steels in FGD and Acid Rain Environments (산성비 및 배연탈황설비 환경에서 Ni 첨가에 따른 저합금강의 내식성 비교연구)

  • Han, Jun-Hee;Nguyen, Dang-Nam;Jang, Young-Wook;Kim, Jung-Gu
    • Korean Journal of Metals and Materials
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    • v.47 no.9
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    • pp.558-566
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    • 2009
  • The alloying effect of a small amount of nickel on low alloy steel for application to flue gas desulfurization(FGD) systems was studied. The structural characteristics of the rust layer were investigated by scanning electron microscopy(SEM). The electrochemical properties were examined by means of potentiostatic polarization test, potentiodynamic polarization test, and electrochemical impedance spectroscopy(EIS) in a modified green death solution of 16.9 vol.% $H_2SO_4$+0.35 vol.% HCl at $60^{\circ}C$ and an acid rain solution of $6.25{\times}10^{-5}M\;H_2SO_4+5.5{\times}10^{-3}M\;NaCl$ at room temperature. It was found that as the amount of nickel increased, the corrosion rate increased in the modified green death solution, which seemed to result from micro-galvanic corrosion between NiS and alloy matrix. In acid rain solution, the corrosion rate decreased as the amount of nickel increased due to the repulsive force of $NiFe_2O_4$ rust against $Cl^-$ ions by electronegativity.

A New Spray Chrysanthemum Cultivar, "Cherry Blossom" with Resistant to White Rust, Single Flower Type and Bright Pink Petals for Cut Flower

  • Lim, Jin-Hee;Shin, Hak-Ki;Park, Sang Kun;Cho, Hae-Ryong;Rhee, Hye-Kyung;Kim, Mi-Seon;Joung, Hyang Young
    • Korean Journal of Breeding Science
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    • v.40 no.4
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    • pp.439-442
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    • 2008
  • A new spray chrysanthemum cultivar, 'Cherry Blossom' was released by National Horticultural Research Institute (NHRI), Rural Development Administration (RDA), Korea in 2007. A cross was made in 2002 between 'Relance', a spray cultivar with red petals and resistant to white rust and 'Yeonja', a spray cultivar with pink petals. Trials were conducted from 2005 to 2007 for the evaluation and selection of this cultivar, including shading culture in summer and retarding culture in autumn. The natural flowering time of "Cherry Blossom" is late October, but year-round flowering is possible by shading and lighting treatment. This cultivar is single type flowers with dark pink petals and green flower center and resistant to white rust. It is very stable color of petals when the variety is cultivated under high temperature conditions in summer season. The diameter of flower is 55.0 mm. The number of flowers per stem is 10.5 and the number of petals per flower is 24.0. The days to flowering under the short day treatment is about 45 in spring season.

A New Spray Chrysanthemum, "Pink Berry" with Resistance to White Rust, and Long Vase Life, Single Flower Type and Pink Petals for Cut Flower

  • Lim, Jin-Hee;Shin, Hak-Ki;Park, Sang Kun;Cho, Hae-Ryong;Rhee, Hye-Kyung;Kim, Mi-Seon;Joung, Hyang-Young
    • Korean Journal of Breeding Science
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    • v.41 no.2
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    • pp.141-144
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    • 2009
  • A new spray chrysanthemum 'Pink Berry' was released by National Institute of Horticultural and Herbal Science (NIHHS), Rural Development Administration (RDA), Korea in 2007. A cross was made in 2004 between 'Lineker Salmon', a spray cultivar with salmon petals, and 'Baeksokuk', a spray cultivar with white petals. Trials were conducted from 2005 to 2007 for evaluation and selection of this cultivar, including shade cultivation in summer and retarding cultivation in autumn. The natural flowering time of 'Pink Berry' is late October, but year-round flowering is possible by photo-periodic control. The cultivar has single type flowers with pink petals and a green flower center. It shows long vase life of 22 days and resistance to white rust. The diameter of flower is 52.0 mm. The numbers of flowers per stem and petals per flower are 15.5 and 29.5, respectively. Days to flowering under the short day treatment is about 56 in autumn seasons.

A New Spray Chrysanthemum, "Pure Angel" with Resistant to White Rust, Single Flower Type and Pure White Petals for Cut Flower

  • Lim, Jin-Hee;Shin, Hak-Ki;Park, Sang Kun;Cho, Hae-Ryong;Rhee, Hye-Kyung;Kim, Mi-Seon;Joung, Hyang Young
    • Korean Journal of Breeding Science
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    • v.41 no.2
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    • pp.173-176
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    • 2009
  • A new spray chrysanthemum cultivar 'Pure Angel' was released by National Institute of Horticultural and Herbal Science (NIHHS), Rural Development Administration (RDA), Korea in 2007. The cross was made in 2004 between 'Innocence', a breeding cultivar of NIHHS, and 'Baeksokuk', a spray cultivar with white petals. Trials were conducted from 2005 to 2007 for the evaluation and selection of this cultivar, including shade cultures in summer and retarding cultures in autumn. The natural flowering time of 'Pure Angel' is late October, but year-round flowering is possible by photo-periodic control. The cultivar has single type flowers with pure white petals and a green flower center. It shows long vase life and resistance to white rust. The diameter of flower is 52.5 mm. The numbers of flowers per stem and petals per flower are 12 and 22.5, respectively. Days to flowering under the short day treatment is about 52 days in spring seasons.

Rust of Belamcanda chinensis Caused by Puccinia belamcandae (Puccinia belamcandae에 의한 범부체 녹병)

  • Kwon, Jin-Hyeuk;Park, Chang-Seuk
    • The Korean Journal of Mycology
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    • v.32 no.1
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    • pp.54-56
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    • 2004
  • Rust disease was occurred on blackberry lily (Belamcanda chinensis) in several farmer's fields located in Heohwa-myon, Goseong-gun, Gyeongnam province in Korea. The typical symptoms of the disease appeared as small, yellowish spot on leaves at first. The spots then turned brown, their edges rised slightly, and powdery mass of yellow or yellowish green spores appeared on the lesions. Severely infected leaves were blighted and eventually died. Urediniospores were yellow or yellowish brown in color, globoid to ovoid in shape and $21{\sim}46{\times}18{\sim}38\;{\mu}m$ in size. Teliospores were brown in color, oblong or clavate in shape and $32{\sim}64{\times}12{\sim}26\;{\mu}m$ in size. The causal fungus was identified as Puccinia belamcandae based on morphological characteristics and host specificity. This is the first report on the rust of B. chinensis caused by P. belamcandae in Korea.