• Title, Summary, Keyword: birnessite

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Dechlorination of the Fungicide Chlorothalonil by Zerovalent Iron and Manganese Oxides (Zerovalent Iron 및 Manganese Oxide에 의한 살균제 Chlorothalonil의 탈염소화)

  • Yun, Jong-Kuk;Kim, Tae-Hwa;Kim, Jang-Eok
    • The Korean Journal of Pesticide Science
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    • v.12 no.1
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    • pp.43-49
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    • 2008
  • This study is conducted to determine the potential of zerovalent iron (ZVI), pyrolusite and birnessite to remediate water contaminated with chlorothalonil. The degradation rate of chlorothalonil by treatment of ZVI, pyrolusite and birnessite was much higher in low condition of pH. Mixing an aqueous solution of chlorothalonil with 1.0% (w/v) ZVI, pyrolusite and birnessite resulted in 4.7, 13.46 and 21.38 hours degradation half-life of chlorothalonil, respectively. Dechlorination number of chlorothalonil by treaonent of ZVI, pyrolusite and birnessite exhibited 2.85, 1.12 and 1.09, respectively. Degradation products of chlorothalonil by teartment of pyrolusite and birnessite were confirmed as trichloro-1,3-dicyanobenzene and dichloro-1,3-dicyanobenzene which were dechlorinated one and two chlorine atoms from parent chlorothalonil by GC-mass. Degradation products of chlorothalonil by ZVI were identified not only as those by pyrolusite and birnessite but as further reduced chloro-1,3-dicyanobenzene and chlorocyanobenzene.

Sorption of aqueous uranium(VI) ion onto a cation-exchangeable K-birnessite colloid (양이온 교환능을 갖는 K-Birnessite 콜로이드에 의한 수용성 우라늄(VI) 이온의 흡착 연구)

  • Kang, Kwang-Cheol;Kim, Seung-Soo;Baik, Min-Hoon;Kwon, Soo-Han;Rhee, Seog-Woo
    • Analytical Science and Technology
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    • v.23 no.6
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    • pp.566-571
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    • 2010
  • This paper describes the sorption behaviors of aqueous uranium ions on the K-birnessite. K-birnessite was synthesized by adding a concentrated HCl to an aqueous solution of $KMnO_4$. Physicochemical characteristics of the K-birnessite, such as structure, specific surface area and surface charge, were investigated. K-birnessite is a layered material and the $K^+$ ions exist in the interlayer of layered K-birnessite. BET specific surface area of the K-birnessite was 38.30 m2/g. The surface charge of K-birnessite was $-1.65\;C/m^2$ at pH 5.00 and ionic strength of 0.010 M $NaClO_4$, at which the sorption experiments of uranium ions were carried out. Uranium ions were incorporated into the interlayer of the K-birnessite by cation-exchange reaction with $K^+$ ions, and the distribution coefficient is quite similar to those of common ion-exchange materials. The results might be applicable in the retardation of migration of radioactive materials from the underground disposal site of high-level radioactive waste.

A study on removal of cesium and strontium from aqueous solution using synthetic Na-birnessite (나트륨-버네사이트를 이용한 수용액상의 세슘 및 스트론튬 제거에 관한 연구)

  • Cho, Yunchul;Seol, Bit Na
    • Journal of Korean Society of Water and Wastewater
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    • v.27 no.2
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    • pp.155-164
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    • 2013
  • The main purpose of this research was to examine the adsorption/ion exchange characteristics of radioactive species such as cesium and strontium onto synthetic Na-birnessite (sodium-birnessite). As part of efforts to investigate the sorption behavior of cesium and strontium onto synthetic Na-birnessite, batch isotherm tests were performed under different experimental conditions. Na-birnessite was synthesized by the oxidation of $Mn^{2+}$ ions in sodium hydroxide solution. The synthetic Na-birnessite was characterized by powder x-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), and Brunauer-Emmett-Teller (BET) surface area analysis. Cesium and strontium concentrations were determined by atomic absorption spectroscopy (AAS). The removal efficiency of strontium by Na-birnessite was around 95 % which was much higher than that of cesium (~ 32 %). The results imply that strontium has a higher affinity for Na-birnessite than cesium because strontium, divalent cation leads to larger electrostatic attraction than monovalent cesium.

Toxicity Assessment of Pb or Cd Contaminated Sediments Amended with Birnessite or Hydroxyapatite (Birnessite와 Hydroxyapatite에 의한 납과 카드뮴 오염퇴적토의 독성저감 평가)

  • Lee, Seung-Bae;Jung, Jae-Woong;Kim, Young-Jin;Nam, Kyoung-Phile
    • Journal of Soil and Groundwater Environment
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    • v.17 no.4
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    • pp.1-8
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    • 2012
  • The success of stabilization treatment in heavy metal contaminated sediment depends on the heavy metal bioavailability reduction through the sequestration of the heavy metals. This study was performed to assess the changes in the bioavailability of Pb or Cd in the Pb or Cd contaminated sediments by using birnessite and hydroxyapatite as stabilizing agents. The toxicity tests were carried out using a microorganism (Vibrio fischeri), an amphipod (Hyalella azteca) and an earthworm (Eisenia foetida). With Vibrio fischeri, the toxicities of both Pb and Cd were reduced by more than ten times in the presence of birnessite and hydroxyapatite compared to that of in the absence of birnessite and hydroxyapatite. The concentrations of Pb and Cd in the contaminated sediments were lethal to Hyalella azteca, however, in the presence of birnessite and hydroxyapatite more than 90%, on average, of Hyalella azteca survived. With Eisenia foetida, the bioaccumulated concentrations of both Pb and Cd were reduced by more than 75%, on average, lower with the addition of birnessite and hydroxyapatite to the contaminated sediments. These results show that the addition of birnessite and hydroxyapatite can reduce the bioavailability of Pb and Cd in contaminated sediments. In addition, the in situ and ex situ performance of birnessite and hydroxyapatite as stabilizing agents can be verified using the toxicity tests with Hyalella azteca and Eisenia foetida, respectively.

Oxidative Coupling of Herbicide Propanil and Its Metabolite, DCA(3,4-dichloroaniline) to Humic Monomers (제초제 Propanil 및 그 분해산물인 DCA(3,4-dichloroaniline)와 Humic Monomer들과의 산화적 짝지움반응)

  • Kwon, Tae-Dong;Kim, Jang-Eok
    • Applied Biological Chemistry
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    • v.41 no.5
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    • pp.384-389
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    • 1998
  • The herbicide propanil and its metabolite, DCA were incubated with oxidative catalysts in the presence or absence of humic monomers to evaluate the incorporation of them into humic substances. Propanil and DCA underwent little or no transformation by oxidatve catalysts in the absence of humic monomers. In the presence of humic monomers, the most effective co-substrate for transformation of propanil was syringic acid by laccase and HRP, that of DCA was catechol by laccase and HRP, and protocatechuic acid by birnessite. The transformation of DCA was the highest when it was incubated with catechol at pH 8.0 during 24 hrs by laccase, and with catechol at pH 3.0 during 2 hrs by HRP, and with protocatechuic acid at pH 5.0 during 2 hrs by birnessite. The DCA transformation increased with increasing concentration of humic monomers. The transformation of DCA was increased with about 5 times when it was incubated with lactase and birnessite together than lactase alone, but that of it was not effected when it was incubated with HRP and birnessite together. When DCA was incubated with dissolved organic carbon in the presence of oxidative catalysts, the transformation of it was not increased by laccase and birnessite but increased by HRP.

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Hydrothermal Synthesis of Li-Mn Spinel Nanoparticle from K-Birnessite and Its Electrochemical Characteristics (K-Birnessite를 이용한 Li-Mn Spinel 나노입자 합성 및 전기화학적 특성 평가)

  • Kim, Jun-Il;Lee, Jae-Won;Park, Sun-Min;Roh, Kwang-Chul;Sun, Yang-Kook
    • Applied Chemistry for Engineering
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    • v.21 no.5
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    • pp.590-592
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    • 2010
  • Li-Mn spinel ($LiMn_2O_4$) is prepared by a hydrothermal process with K-Birnessite ($KMnO_4{\cdot}yH_2O$) as a precursor. The K-Birnessite obtained via a hydrothermal process with potassium permanganate [$KMnO_4$] and urea [$CO(NH_2)_2$] as starting materials are converted to Li-Mn spinel nanoparticles reacting with LiOH. The molar ratio of LiOH/K-Birnessite is adjusted in order to find the effect of the ratio on the structural, morphological and electrochemical performances of the Li-Mn spinel. X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), and thermogravimetry (TG) are used to investigate the crystal structure and morphology of the samples. Galvanostatic charge and discharge are carried out to measure the capacity and rate capability of the Li-Mn spinel. The capacity shows a maximum value of $117\;mAhg^{-1}$ when the molar ratio of LiOH/K-Birnessite is 0.8 and decreases with the increase of the ratio. However the rate capability is improved with the increase of the ratio due to the reduction of the particle size.

Phase Transition and Surface Morphological Characteristics of Intermediate Product Feitknechtite According to Aging Time during the Synthesis of Birnessite (버네사이트 합성 시 에이징 시간에 따른 중간생성물 페이크네타이트 상전이 및 표면 형태학적 특성)

  • Min, Soyoung;Kim, Yeongkyoo
    • Journal of the Mineralogical Society of Korea
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    • v.32 no.3
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    • pp.213-222
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    • 2019
  • Birnessite (birnessite, $7{\AA}$ manganate, ${\delta}-MnO_2$) is a major mineral comprising manganese nodule. Various synthetic methods have been studied and evaluated because it can be used as an ion exchange agent and a battery recharging material. However, it is difficult to obtain a single birnessite phase because it does not have a stoichiometric chemical composition. Feitknechtite (${\beta}-MnOOH$) is formed as an intermediate product during birnessite synthesis and in this study, the transition of this phase to birnessite was compared by using XRD and SEM. Two different methods, Feng et al. (2004) and Luo et al. (1998), based on redox reaction were used. It was possible to obtain the impurity-free birnessite for the sample aged 60 days at $27^{\circ}C$ by Feng et al. (2004) method and 3 days at $60^{\circ}C$ by Luo et al. (1998) method. The phase transition rate of the feitknechtite phase was slower in the case of $Mg^{2+}$ doped birnessite which was synthesized by Luo et al. (1998) method, and almost single phase almost single phase birnessite was identified at high temperature. Crystal surface and morphology also confirmed the difference between the samples synthesized by two methods.

망간산화물을 이용한 1-Naphthol의 산화-공유결합 반응 속도 연구

  • Im Dong-Min;Sin Hyeon-Sang;Jeon Byeong-U;Gang Gi-Hun
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • pp.49-52
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    • 2005
  • In this study, abiotic transformation of 1-naphthol via oxidative-coupling reaction was evaluated using Mn oxide which is ubiquitous in natural soils. The transformation of 1-naphthol catalyzed by synthetic birnessite $({\delta}-MnO_2)$ followed pseudo-lst order reaction, and the rate constants was in the range of $0.053{\sim}0.13\;min^{-1}$ with birnessite loadings of $12.5{\sim}50\;mg/20\;mL$. Since the oxidation of 1-naphthol was occurred on the reactive surface of the oxide particles, the rate constants with various birnessite loadings were correlated with birnessite surface area concentration. The correlation showed a strong linearity, which confirms the supposition of the surface reaction. From the correlation, therefore, the surface area normalized rate constant, $k_{surf}$, was determined to be 0.032 $L/m^2\;min$.

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A Review of Geochemical Factors Governing the Phase Transformation of Birnessite (버네사이트 상변화 반응의 지화학적 반응 조절인자 연구)

  • Namgung, Seonyi;Chon, Chul-Min;Lee, Giehyeon
    • Economic and Environmental Geology
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    • v.50 no.6
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    • pp.545-554
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    • 2017
  • Birnessite is one of the dominant Mn (oxyhydr)oxide phases commonly found in soil and deep ocean environments. It typically occurs as nano-sized and poorly crystalline aggregates in the natural environment. It is well known that birnessite participates in a wide variety of bio/geochemical reactions as a reactive mineral phase with structural defects, cation vacancies, and mixed valences of structural Mn. These various bio/geochemical reactions control not only the fate and transport of inorganic and organic substances in the environment, but also the formation of diverse Mn (oxyhydr)oxides through birnessite transformation. This review assessed and discussed about the phase transformation of birnessite under a wide range of environmental conditions and about the potential geochemical factors controlling the corresponding reactions in the literature. Birnessite transformation to other types of Mn (oxyhydr)oxides were affected by dissolved Mn(II), dissolved oxygen, solution pH, and co-existing cation (i.e., $Mg^{2+}$). However, there still have been many issues to be unraveled on the complex bio/geochemical processes involved in the phase transformation of birnessite. Future work on the detail mechanisms of birnessite transformation should be further investigated.

A Study on the Oxidative Transformation of Quinone Compound using Nanostructured Black-birnessite (나노구조의 블랙-버네사이트를 이용한 퀴논계 화합물의 산화-변환 연구)

  • Harn, Yoon-I;Choi, Chan-Kyu;Shin, Hyun-Sang
    • Journal of Korean Society of Environmental Engineers
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    • v.32 no.6
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    • pp.547-554
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    • 2010
  • In this study, new manganese oxide (i.e., black-birnessite) particles with nanostructures were prepared and its physico-chemical properties and oxidative-transformation efficiency on 1,4-naphthoquinine(1,4-NPQ) in the presence of reactive mediator was investigated. The results were also compared with that of the manganese oxide (i.e., brown-birnessite) particles synthesized by classical McKenzie method. Analysis of XRD and SEM data show that the particles are a single phase corresponding to a birnessite-based manganese oxide with cotton ball-like shapes containing nanofibers. In batch experiments, removals of 1,4-NPQ by the black-birnessite follows pseudo-first-order kinetics and the rate constant values obtained are greater about 2.3 times than that of the brown-birnessite in spite of its lower surface area (41.0 vs 19.80 $m^2/g$). The results can be explained by the higher crystallinity and nano structured features of the back-birnessite particles, which give higher reactivity for the removals of the quinone compound. HPLC analysis of the reaction products confirmed that the balck-birnessites removed 1,4-NPQ through cross-coupling reaction in the presence of catechol as a reactive mediator.