• Title/Summary/Keyword: $Fe^{2+}$ ion concentration

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Influence of pH on Leaching Behavior of Phosphorous from Steelmaking Slag (제강슬래그에서 인의 침출 거동에 대한 pH의 영향)

  • Kim, Jeong-In;Kim, Sun-Joong
    • Resources Recycling
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    • v.25 no.6
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    • pp.23-28
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    • 2016
  • In this study, leaching process to extract phosphorus from the steelmaking slag was investigated for using the fertilizer resources of agriculture. In general, the phosphorus of steelmaking slag is formed as $C_2S-C_3P$ solid solution, and also, this solid solution is soluble in water more than the other phase in slag, and less than free CaO phase. In the present experiment, the influence of pH on the leaching behavior of various elements from the steelmaking slag was investigated by using multi-component steelmaking slag. When the pH was decreased, the concentration of Ca, Si, P and Fe in solution from the steelmaking slag was increased. Furthermore, at a pH of 3, the concentration of P ion in solution was decreased as leaching time increased. It is considered that the decrement of P was caused from the precipitation reaction between P ion and Fe ion in solution.

Seasonal Variation and Statistical Analysis of Particulate Pollutants in Urban Air (도시대기립자상물질중 오염성분의 계절적 변동 및 통계적 해석)

  • 이승일
    • Journal of environmental and Sanitary engineering
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    • v.9 no.2
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    • pp.8-23
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    • 1994
  • During the period from Mar., 1991 to Feb., 1992 66 tSP samples were collected by Hi volume air sampler at 1 sampling site in Seoul and the amount of concentration of 21 components(SO$_{4}$$^{2-}$, NO$_{3}$$^{-}$, NH$_{4}$$^{+}$, Cl$^{-}$, Al, Ba, Ca, Cd, Cr, Cu, Fe, It Mg, Mn, Na, Ni, Pt Si, Ti, Zn, Zr ) were measured. And monthly and seasonal variation were surveyed and the principal component analysis( PCA ) were carried out with respect to these amount of pollutants, minimum of visibility and radiation on a horizontal surface. The total amount of soluble ion in water was high in order o(SO$_{4}$$^{2-}$> NO$_{3}$$^{-}$> N%'>Cl$^{-}$ and metal ion was high in order of Na> Ca>Si> Fe> Al> K> Mg> Zn> Pb> Cu>Ti> Mn > Ba> Cr> Zr> Ni> Cd. There was Seasonal variation in concentration for SO$_{4}$$^{2-}$, NH$_{4}$$^{+}$, Cl$^{-}$, Na, Al, Ca, Bt Mg, Fe and Si. It was assumed that the components of the highest concentration on April were depend on yellow sand and the frequency of wind velocity and direction. As the results of PCA, the amount of pollution components was able to characterized with two principal components(Z$_{1}$, Z$_{2}$ ). The first principal components Z$_{1}$ was considered to be a factor indicating the pollutants originated from natural generation and The second principal components Z$_{2}$ was considered to be a factor indicating the pollutants originated from human work. The monthly concentration of pollutants in ISP, minimum of visibility and radiation on a horizontal surface was possible to evaluate by the use of these two principal components Z$_{1}$ and Z$_{2}$ .

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Effect of Composition on the pH and Solution Potential of Mixed Solutions of Copper and Iron Chloride (염화(鹽貨)구리와 염화철(鹽貨鐵) 혼합용액(混合溶液)의 조성(組成)이 pH와 용액전위(溶液電位)에 미치는 영향(影響))

  • Lee, Man-Seung;Son, Seong-Ho
    • Resources Recycling
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    • v.17 no.6
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    • pp.17-23
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    • 2008
  • In order to simulate the leaching solution of copper sulfide ore in $FeCl_3$ solutions, synthetic solutions with composition of $FeCl_3$-$FeCl_2$-$CuCl_2$-CuCl-NaCl-HCl-$H_2O$ were prepared. The concentration of iron and copper chloride was varied from 0.1 to 1 m in synthetic solutions. The effect of composition on the mixed solution pH and potential at $25^{\circ}C$ was measured. When HCl concentration was constant, the increase of CuCl concentration increased solution pH. The increase of other solutes excluding HCl and CuCl decreased solution pH owing to the increase of the activity coefficient of hydrogen ion. A high CuCl concentration favored the redox equilibrium in the direction of Cu(I), while $FeCl_3$ had the opposite effect.

Origin of the Initial Permeability of Manganese-Zinc Ferrite Polycrytals (Mn-Zn 페라이트 다결정의 조성에 따른 투자율의 변화 기구)

  • 변순천;제해준;고경현;홍국선
    • Journal of the Korean Ceramic Society
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    • v.34 no.4
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    • pp.351-356
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    • 1997
  • The origin of the variation of initial permeability in manganese-zinc ferrite polycrystals with a content of hematite was investigated. Initial permeability showed maximum with hematite content while there was no significant change in microstructure. Saturation magnetization increased with hematite content. So the variation of initial permeability was not explained on the basis of microstructural change or saturation magnetization. Temperature dependence of initial permeability revealed magnetocrystalline anisotropy was the origin of the variation of initial permeability. The change in magnetocrystalline anisotropy was ascribed to the variation in ferrous ion concentration. Therefore the variation of initial permeability in manganese-zinc ferrite polycrystals with a content of hematite was due to ferrous ion concentration via magnetocrystalline anisotropy.

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Kinetics of N2O Decomposition over Fe-TNU-9 Zeolite (Fe-TNU-9 제올라이트 상에서 아산화질소의 분해반응 속도론)

  • Park, Jung-Hyun;Jeon, Seong-Hee;Van Khoa, Nguyen;Shin, Chae-Ho
    • Applied Chemistry for Engineering
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    • v.20 no.4
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    • pp.453-458
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    • 2009
  • Iron-containing TNU-9 zeolites were prepared by aqueous ion exchange in the range of Fe contents 0.6~3.3 wt%. Direct decomposition of $N_2O$ was performed varying $N_2O$ concentrations and reaction temperatures. Fe-TNU-9 zeolites used were characterized using XRD, $N_2$ sorption, SEM/EDX. A 2.7 wt% Fe-TNU-9 zeolite showed high activities and above this contents of Fe the effect of catalytic activity was little dominated. Fe-TNU-9 zeolites after ion exchange conserved their TNU-9 structure although the degree of crystallinity was decreased until ca. 60% in 3.1 wt% Fe-TNU-9 zeolite after ion exchange in 0.01 M Fe solution. The decrease in the degree of crystallinity could be correlated with the decrease of surface area and pore volume. The partial reaction order of $N_2O$ in the decomposition of $N_2O$ was dependent on the reaction temperature from 0.69 at $420^{\circ}C$ to 0.97 at $494^{\circ}C$. The activation energy of $N_2O$ was also dependent on the $N_2O$ concentration and its value is ranged to 34~43 kcal/mol.

Iron-loaded Natural Clay as Heterogeneous Catalyst for Fenton-like Discoloration of Dyeing Wastewater

  • Xu, Huan-Yan;Ha, Xiu-Lan;Wu, Ze;Shan, Lian-Wei;Zhang, Wei-Dong
    • Bulletin of the Korean Chemical Society
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    • v.30 no.10
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    • pp.2249-2252
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    • 2009
  • The clay-based Fe-bearing catalyst was successfully prepared through ion-exchange reaction and applied as heterogeneous catalyst for discoloration of acid fuchsine (AF) in an aqueous solution by Fenton-like reaction. Experimental results demonstrated that the AF discoloration ratios increased by increasing Fe-loaded clay dosage and initial $H_2O_2$ concentration, and by decreasing the pH, respectively. The lower the initial AF concentration, the shorter the reaction time needed to achieve complete discoloration of AF. Comparative studies indicated that AF discoloration ratios were much higher in presence of Fe-loaded clay and $H_2O_2$ than those in presence of $H_2O_2$, raw natural clay or Fe-loaded clay only and raw natural clay and $H_2O_2$ jointly. After AF discoloration, there existed no new phases in the clay samples detected by XRD and no change in the clay crystal morphology observed by SEM. A mechanism proposed suggested adsorption and Fenton-like reaction were responsible for discoloration of AF.

Effect of Silicate Ions on the Hydration of 4CaO · Al2O3 · Fe2O3 with Gypsum

  • You, Kwang-Suk;Ahn, Ji-Whan;Kim, Hwan;Goto, Seishi
    • Journal of the Korean Ceramic Society
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    • v.41 no.9
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    • pp.642-646
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    • 2004
  • Na$_2$Si$_2$O$_{5}$ added to the solution affects the hydration of 4CaOㆍAl$_2$O$_3$ㆍFe$_2$O$_3$ with calcium sulfate. The reaction between 4CaOㆍAl$_2$O$_3$ Fe$_2$O$_3$and CaSO$_4$ㆍ 2$H_2O$ decrease with increasing amount of Na$_2$Si$_2$O$_{5}$ in solution, owing to low hydraulic reactivity of 4CaOㆍAl$_2$O$_3$ㆍFe$_2$O$_3$by the adsorption of silicate ions on the surface of 4CaOㆍAl$_2$O$_3$ㆍ Fe$_2$O$_3$ particles. The dissolution rate of 4CaOㆍAl$_2$O$_3$ㆍ Fe$_2$O$_3$ particles deceased with the increase of the concentration of silicate ion in solution. When the 4CaOㆍAl$_2$O$_3$ㆍFe$_2$O$_3$ particles was hydrated in gypsum - Na$_2$Si$_2$O$_{5}$ solution, the hydration was retarded and the rate could not discriminate between formation of ettringite and that of monosulfate, and it stopped in high concentration of silicate ions. However, silicate ion did not any effect on the dissolution rate of gypsum.ypsum.

Studies on Phytotoxin in Intensively Cultivated Upland Soil III. The Abilities of Siderophore Formation, Competition and Absorption of Fe3+ and Mn2+ with Inoculation of the Fluorescence Forming Soil Bacteria and Soil Saprophytic Fungi (연작장해지토양(連作障害地土壤)의 식물독소(植物毒素)에 관(關)한 연구(硏究) 제(第)3보(報) Siderophore 생성(生成) Pseudomonas 속(屬) 세균접종(細菌接種) 및 양(陽) ion 첨가(添加)가 토양부생균(土壤腐生菌)의 생육(生育)에 미치는 영향(影響))

  • Lee, Sang-Kyu;Suh, Jang-Sun
    • Korean Journal of Soil Science and Fertilizer
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    • v.21 no.1
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    • pp.41-47
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    • 1988
  • A laboratory experiment was conducted to find out the abilities of siderophore formation and competition of $Fe^{3+}$ and $Mn^{2+}$ absorption in synthetic medium with inoculation of fluorescence forming pseudomonas and soil saprophytic fungi as Stachybotrys chatarum, Fusarium solani, and F. oxysporum. The results obtained were summarized as follows; 1. The concentration of siderophore in synthetic medium with inoculation of Pseudomonas putida pt-II was increased (with progress of incubation time). 2. The negative correlation was obtained with the increase of $Fe^{3+}$ ion concentration and siderophore in synthetic medium with inoculation of fluorescence forming pseudomonas and soil saprophytic fungi. 3. The fresh weight of fungal hyphae was decreased with the increase of siderophore in synthetic medium. 4. There was insignificant relationship between the concentration of $Mn^{2+}$ and the concentration of siderophore while the positive correlation was obtained with the increase of fresh weight of fungal hyphae.

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Repassivation Characteristics of Fe-Cr Steels Using the Abrading Electrode Technique in Aqueous 0.1M $Na_2SO_4+ NaCl$ Solutions (0.1M $Na_2SO_4+ NaCl$ 수용액에서 마멸 전극 기법을 이용한 Fe-Cr강의 재부동태 특성)

  • Ham Dong Ho;Lee Jae Bong
    • Journal of the Korean Electrochemical Society
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    • v.2 no.4
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    • pp.195-201
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    • 1999
  • The repassivation characteristics of Fe-Cr steels in deaerated 0.1 M $Na_2SO_4$ solution have been investigated with the variation of Cr content, applied potential and Cl- concentration. In the absence of chloride ion, abrading electrode test showed that, slope -n, of log i=k -n log t, a parameter of repassivation rate, approached to -1, regardless of Cr content but as Cr content increased, repassivation current density decreases with increasing Cr content. A.C. Impedance spectroscopy showed that the charge transfer resistance of passive film became higher as Cr content and applied potential increased. However, in the presence of chloride ion, it was observed that chloride ion suppressed the passive film formation, whose effect became greater with increasing applied potential.

Decomposition of Hydrogen Peroxide in Fenton Systems (펜톤 시스템에서의 과산화수소 분해연구)

  • Mok, Young-Sun;Jo, Jin-Oh;Kim, Seok-Tae;Jeong, Woo-Tae;Kang, Duk-Won;Rhee, Byong-Ho;Kim, Jin-Kil
    • Journal of Korean Society of Environmental Engineers
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    • v.29 no.1
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    • pp.68-73
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    • 2007
  • In this study, we investigated the decomposition of highly concentrated hydrogen peroxide in the range of 1.04-2.55 M by transition metal ion catalysts such as $Fe^{2+}$ and $Cu^{2+}$. The effect of metal ion concentration on the decomposition of hydrogen peroxide was examined experimentally, and the decomposition rate constants were determined by combining the experimental data with a theoretical approach. The rate of the decomposition of hydrogen peroxide was found to be first order with respect to its concentration. The decomposition rate constant was able to be treated as a linear function of the initial metal ion concentration. The validity of the decomposition rate constants determined was verified by good agreements between the calculated and experimental results.