• 제목/요약/키워드: Sulfate ($SO{_4}^{2-}$)

검색결과 806건 처리시간 0.026초

Relationships between Methane Production and Sulfate Reduction in Reclaimed Rice Field Soils

  • Lee, Ju-Hwan;Cho, Kang-Hyun
    • Animal cells and systems
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    • 제8권4호
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    • pp.281-288
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    • 2004
  • The change in relationships between methane production and sulfate reduction was investigated in reclaimed rice field soils at different time points after reclamation of tidal flat in Korea. Sulfate concentrations of soils in the ca. 60-year-old and 26-year-old reclaimed rice fields were much lower than that in a natural tidal flat. During 60 d of anaerobic incubation, total methane production and sulfate consumption of the soil slurries were 7.0 ${\mu}$mol $CH_4$/g and 8.2 ${\mu}$mol $SO_4^{2-}$/g in the 60-year-old rice field, 5.6 ${\mu}$mol $CH_4$/g and 12.7 mmol $SO_4^{2-}$/g in the 26-year-old rice field, and ca. 0 mmol $CH_4$/g and 22.4 ${\mu}$mol $SO_4^{2-}$/g in a natural tidal flat. Relative percent electron flow through sulfate reduction in the 60-year-old rice field was much lower (50.8%) compared with the 26-year-old rice field (69.3%) and the tidal flat (99.9%). The addition of an inhibitor of methanogenesis (2-bromoethanesulfonate) had no effect on sulfate reduction in the soil slurries of the reclaimed rice fields. However, instant stimulation of methane production was achieved with addition of an inhibitor of sulfate reduction (molybdate) in the soil slurries from the 26-year-old reclaimed rice field. The specific inhibitor experiments suggest that the relationship of methanogenesis and sulfate reduction might become mutually exclusive or syntrophic depending on sulfate content in the soil after reclamation. Sulfate, thus sulfate reduction activity of sulfate-reducing bacteria, would be an important environmental factor that inhibits methane production and determines the major pathway of electron and carbon flow in anaerobic carbon mineralization of reclaimed rice field soils.

Highly Active Catalyst of Nickel Sulfate Supported on Titania for Ethylene Dimerization

  • 손종락;박원천
    • Bulletin of the Korean Chemical Society
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    • 제22권12호
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    • pp.1303-1308
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    • 2001
  • A series of catalysts, NiSO4/TiO2, for ethylene dimerization was prepared by the impregnation method using aqueous solution of nickel sulfate. On the basis of the results obtained from X-ray diffraction, the addition of NiSO4 shifted the transition of TiO2 from the anatase to the rutile phase toward higher temperatures due to the interaction between NiSO4 and TiO2. Nickel sulfate supported on titania was found to be very active even at room temperature. The high catalytic activity of NiSO4/TiO2 closely correlated with the increase of acidity and acid strength due to the addition of NiSO4. It is suggested that the active sites responsible for ethylene dimerization consist of low valent nickel, Ni+, with an acid.

흑연에 황산을 Intercalation 시킬때의 Mechanism 규명 (I. 전기적 산화방법에 의한 Graphite Salts의 중간상에 관한 연구) (Mechanism of Intercalation Compounds in Graphite with Hydrogen Sulfate (I. Study of Intermediate Phase between 2 Stage and 1 Stage in Graphite Hydrogen Sulfate with Anodic Oxidation))

  • 고영신;한경석;이풍헌
    • 한국세라믹학회지
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    • 제22권6호
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    • pp.5-8
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    • 1985
  • Graphite has been oxidized to graphite hydrogen sulfate in concentrated $H_2SO_4$. Anodic oxidation and chemical oxidation of graphite in $H_2SO_4$ generally leads to the formation of intercalation compounds of the ionic salt type through incorporation of $H_2SO_4^-$ions and $H_2SO_4$ molecules into the graphite. Several other reactions also accur at various points of the charging cycle. But there is no satisfactory kinetics and mechanism of intercalationin graphite. We have studied them with anodic oxidation and chemical oxidation. We found six distinct phenomena between 2nd stage and 1st stage in chemical oxidation. We examined them in detail by the following in the measurements electrical oxidation. X-ray diffractions UV-Vis spectroscopy density measurements. We could obtained a equation for kinetic according to the reaction rate from this results and mechanism of intercalation between 2nd stage and 1st stage with hydrogen sulfate in graphite. Three thesis were written for the mechanism of intercalation compounds in graphite with hydrogen sulfate ; first thesis is anodic oxidation second thesis is chemical oxidation and definition of transit phase between 2nd etc the third thesis is the kinetic mechanism of intercalation compounds in graphite with Hydrogen sulfate. This thesis is the first paper among three thesis as anodic oxidation.

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황화광물로부터 유용금속 침출을 위한 Acid Bake-water Leaching System 내 황산염 용매제의 적용성 (Application of Sulfate Solvent in Acid Bake-water Leaching System for Valuable Metal Leaching from Sulfide Mineral)

  • 고진석;톡토흐마;박천영
    • 한국광물학회지
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    • 제31권2호
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    • pp.67-73
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    • 2018
  • 본 연구는 acid bake-water leaching system (AWS)를 이용하여 Au 정광으로부터 경제적이고 친환경적인 유용금속 용출을 위하여 황산염 용매제의 적용성을 파악하는 것이다. AWS 실험은 전기로를 이용하여 다양한 baking 온도($100^{\circ}C{\sim}500^{\circ}C$)와 황산염 용매제($H_2SO_4$, $K_2SO_4$, $(NH_4)_2SO_4$, $MgSO_4$, $CaSO_4$) 조건에서 수행하였다. Baking 온도가 $400^{\circ}C$까지 증가할수록 유용금속의 용출률은 증가하였다. 용출시간에 따른 AWS 실험결과, 최대 용출률 조건은 $(NH_4)_2SO_4$ 용매제이었다. 본 연구를 통하여 $(NH_4)_2SO_4$ 용매제가 AWS를 이용한 유용금속 용출에 있어 효과적인 용매제로 사용가능함을 입증하였다.

황산나트륨과 염화칼륨을 사용한 황산칼륨 제조 연구 (A Study on Synthesis of Potassium Sulfate used Sodium Sulfate and Potassium Chloride)

  • 김남일;김태연;추용식
    • 자원리싸이클링
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    • 제30권1호
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    • pp.35-43
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    • 2021
  • 본 연구에서는 제철 및 시멘트 제조공정에서 발생하는 부산물을 재활용하기 위한 기초 연구로 시약급 Na2SO4와 KCl을 사용하여 K2SO4를 제조하였다. K2SO4 제조 시 최적조건을 도출하기 위해 Na2SO4와 KCl의 몰 비율, 용액의 포화도 및 교반 온도를 제어하였으며, 주사전자현미경, X-선 회절분석기 등을 사용하여 수득시료의 미세구조 관찰 및 결정성을 분석·평가하였다. 순수 K2SO4를 수득할 수 있는 구간은 Na2SO4와 KCl의 몰 비율 1:6-18, 용액의 포화도 160% 이하, 교반 온도 20℃, 50℃이었다. 또한 K2SO4의 높은 결정성 확보 및 최종 수득량 증대, 에너지 소모 최소화를 고려한 최적 조건은 Na2SO4와 KCl의 몰 비율 1:6, 용액의 포화도 140%, 교반 온도 20℃이었다.

Electrochemical Performance of LiMn2O4 Cathodes in Zn-Containing Aqueous Electrolytes

  • Kamenskii, Mikhail A.;Eliseeva, Svetlana N.;Volkov, Alexey I.;Kondratiev, Veniamin V.
    • Journal of Electrochemical Science and Technology
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    • 제13권2호
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    • pp.177-185
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    • 2022
  • Electrochemical properties of LiMn2O4 cathode were investigated in three types of Zn-containing electrolytes: lithium-zinc sulfate electrolyte (1M ZnSO4 / 2M Li2SO4), zinc sulfate electrolyte (2MZnSO4) and lithium-zinc-manganese sulfate electrolyte (1MZnSO4 / 2MLi2SO4 / 0.1MMnSO4). Cyclic voltammetry measurements demonstrated that LiMn2O4 is electrochemically inactive in pure ZnSO4 electrolyte after initial oxidation. The effect of manganese (II) additive in the zinc-manganese sulfate electrolyte on the electrochemical performance was analyzed. The initial capacity of LiMn2O4 is higher in presence of MnSO4 (140 mAh g-1 in 1 M ZnSO4 / 2 M Li2SO4 / 0.1 M MnSO4 and 120 mAh g-1 in 1 M ZnSO4 / 2MLi2SO4). The capacity increase can be explained by the electrodeposition of MnOx layer on the electrode surface. Structural characterization of postmortem electrodes with use of XRD and EDX analysis confirmed that partially formed in pure ZnSO4 electrolyte Zn-containing phase leads to fast capacity fading which is probably related to blocked electroactive sites.

Portland Cement Clinker 생성반응에 미치는 $CaSO_4$$BaSO_4$의 영향 (Effect of $CaSO_4$ and $BaSO_4$ on the Formation of Portland Cement Clinker)

  • 서일영;최상흘
    • 한국세라믹학회지
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    • 제11권1호
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    • pp.29-35
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    • 1974
  • Effect of calcium sulfate and barium sulfate on the formation of portland cement clinker was studied by means of chemical analysis. DTA and X-ray diffraction analysis. In the presence of liquid phase, effect of the additives on the formation of tricalcium silicate was examined according to the reaction, 2CaO.$SiO_3$+CaO$\longrightarrow$3CaO.$SiO_3$, which is the principal reaction in portland cement clinkerization, and optimum conditions in firing clinker concerning amount of additive, firing time and temperature were determined, and its kinetics was referred to. The experimental results are summerized as follow: (1) Appropriate burning temperature range of cement clinker is more limited as the content of calcium sulfate in clinker is increased. Amount of calcium sulfate, firing time and temperature in proper condition of clinkerization is related to each others. Being added suitable quantity of calcium sulfate, firing temperature of clinker can be lowered about $100^{\circ}C$. (2) When 3-5 mole% of calcium sulfate is added, firing time of 15-30 minutes at about $1380^{\circ}C$ is reasonable, and if the content is over7 mole %, firing for 1 hr. or more at $1350^{\circ}C$ is anticipated to be optimum condition. (3) In the reaction of tricalcium silicate formation, the role of barium sulfate as a mineralizer is similar to that of calcium sulfate, but the optimum firing temperature of cement clinker containing barium sulfate tends to be 20-$30^{\circ}C$ higher than that of clinker containing calcium sulfate. (4) When barium sulfate is used as mineralizer, 2-3 mole % of it to tricalcium silicate is recommended and if it is added more than this amount, free CaO is increased rapidly in clinker and alite formation is inhibited.

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전이금속염 첨가에 의한 판상 α-Al2O3 결정체 제조 (Preparation of Flaky α-Al2O3 Crystals by Transition Metal Salts Addition)

  • 송효경;박병기;이정민
    • 한국세라믹학회지
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    • 제42권6호
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    • pp.384-390
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    • 2005
  • [ ${\alpha}-Al_2O_3$ ] precursor was synthesised by sol-gel method using aluminum sulfate, sodium sulfate and sodium carbonate as law materials. The flaky ${\alpha}-Al_2O_3$ crystals were prepared by heating using precursor about $1,050^{\circ}C$. In this study, the effect of some transition-metal sulfate ($FeSO_4,\;SnSO_4,\;ZnSO_4$) addition have been investigated. When iron sulfate was added, it could see that act on impurities in crystal growth process. In case of tin sulfate, distribution of Platelets was very broad. When flaky ${\alpha}-Al_2O_3$ crystals were prepared zinc sulfate addition, thickness, size, and distribution of platelets was suited to industrial application. The average diameter of flaky ${\alpha}-Al_2O_3$ crystals was about 20 $\mu$m, and its thickness was about 0.3 $\mu$m. Increasing addition of zinc sulfate, thickness of ${\alpha}-Al_2O_3$ platelet was decreased.

Experimental Determination of Equilibrium Constants of Copper Complexes in Aqueous Environment

  • Cho, Young-Il
    • 한국환경과학회지
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    • 제21권5호
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    • pp.555-562
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    • 2012
  • The experimental determination of equilibrium constants is required to estimate concentrations of reagents and/or products in environmental chemical reactions. For an example, the choice of copper (Cu) complexation reactions was motivated by their fast kinetics and the ease of measurement of Cu by an ion-sensitive electrode. Each individual titrant of sulfate ($SO{_4}^{2-}$) and oxalate ($C_2O{_4}^{2-}$) was expected to have its own unique characteristics, depending on the bonding in Culigands connected to the aqueous species. The complexation reaction of Cu with $SO{_4}^{2-}$ somewhat fast reached equilibrium status compared with $C_2O{_4}^{2-}$. The experimental equilibrium constants ($K_{eq}$) of copper sulfate ($CuSO_4$) and copper oxalate ($CuC_2O_4$) were determined $10^{2.2}$ and $10^{3{\sim}4.3}$, respectively.

황산동 수용액으로부터 hydrazine 환원에 의한 Cu 미립자의 합성 (Synthesis of Uniform Cu Particles by Hydrazine Reduction from Copper Sulfate Solution)

  • 유연태;최영윤
    • 한국재료학회지
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    • 제13권8호
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    • pp.524-530
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    • 2003
  • In order to prepare the uniform copper particles from copper sulfate solution by using hydrazine as a reduction agents, the reduction behavior of copper particles from copper sulfate was investigated in detail at room temperature by the observation of reaction products. The effects of $NH_4$OH and $Na_4$$P_2$$O_{7}$ on the formation of uniform copper particles were discussed. ($NHCu_3$)$_4$$SO_4$was completely formed at over pH 11 by adding $NH_4$OH in copper sulfate solution. The fine $Cu_2$O with the particle size of 50 nm was produced in the initial reduction process of (NH$Cu_3$)$_4$$SO_4$solution with $Na_4$$P_2$$O_{ 7}$ and then the Cu$_2$O was converted into copper particles by inserting additional hydrazine. When Cu(NH$_3$)$_4$SO$_4$solution with $Na_4$$P_2$$O_{ 7}$ was reduced at $80^{\circ}C$ by hydrazine, the highly dispersed copper particles with the particle size of about 0.8 $\mu\textrm{m}$ was obtained.