• Title, Summary, Keyword: iron oxide

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Synthesis of Iron Oxide and Adsorption of Arsenic on Iron Oxide (철산화물의 합성 및 이를 이용한 비소의 흡착제거)

  • Kim, Youn Jung;Choi, Sik Young;Kim, Young-Hun
    • Journal of Environmental Science International
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    • v.28 no.1
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    • pp.99-106
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    • 2019
  • Arsenic is among the heavy metals commonly found in aqueous environments. Iron oxide is known as an efficient adsorbent for the arsenic. A new synthetic method was applied to provide iron oxide giving a large specific surface area. The mixing method affects the formation of iron oxide. Ultrasonic waves assisted the formation of very fine iron oxide in an organic phase. The synthesized iron oxide is amorphous type with a high surface area of more than $181.3m^2/g$. Sorption capacity of the synthesized adsorbent was relatively very high for arsenic and varied depending on the oxidation state of arsenic: a higher capacity was obtained with As(V). Lower solution pH provided a higher sorption capacity for As(V). The competitive effect of co-exist anions such as chloride, nitrate, and sulfate was minimal in sorption capacity of the iron oxide for arsenic.

Reaction Iron Oxide and Magnesium Oxide in Ceramics Body with Glaze (도자기 소지구성 산화철, 산화마그네슘이 유약과의 반응)

  • Jung, Seok;Hwang, Dong-Ha;Lee, Byung-Ha
    • Korean Journal of Materials Research
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    • v.24 no.7
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    • pp.363-369
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    • 2014
  • This is the study on diffusion of ceramic body oxide compounds to glaze. For ceramic bodies, no ferrous oxides contain white ware, celadon, and 3 wt% iron oxides contained white ware was used in this experiment. These ceramic bodies were glazed by transparency glaze, iron oxides contained glaze, and glaze made by pine tree ash that treated in 1240 degree, under reduction condition for an hour. An electron probe microanalyzer(EPMA) was used to study diffusion of oxides and to calculate distance of ceramics bodies. As a result, only iron oxide and magnesium oxide from the body diffused to glaze, and also made a band which shown very thin layer of iron oxide and magnesium oxide between the body and glaze. The densest band of iron oxide formed 100 to $150{\mu}m$ in the glaze, and the densest band of magnesium oxide was found 50 to $100{\mu}m$ in the glaze. Therefore, it could be concluded that iron oxide in the body is diffused to the glaze and it affects the color of glaze, even though iron oxide exists in the glaze. Furthermore, the thickness of the glaze has an effect on the color of celadon.

Post Annealing Effects on Iron Oxide Nanoparticles Synthesized by Novel Hydrothermal Process

  • Kim, Ki-Chul;Kim, Young-Sung
    • Journal of Magnetics
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    • v.15 no.4
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    • pp.179-184
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    • 2010
  • We have investigated the effects of post annealing on iron oxide nanoparticles synthesized by the novel hydrothermal synthesis method with the $FeSO_4{\cdot}7H_2O$. To investigate the post annealing effect, the as-synthesized iron oxide nanoparticles were annealed at different temperatures in a vacuum chamber. The morphological, structural and magnetic properties of the iron oxide nanoparticles were investigated with high resolution X-ray powder diffraction (XRD), high resolution transmission electron microscopy (HRTEM), Mossbauer spectroscopy, and vibrating sample magnetometer analysis. According to the XRD and HRTEM analysis results, as-synthesized iron oxide nanoparticles were only magnetite ($Fe_3O_4$) phase with face-centered cubic structure but post annealed iron oxide nanoparticles at $700^{\circ}C$ were mainly magnetite phase with trivial maghemite ($\gamma-Fe_2O_3$) phase which was induced in the post annealing treatment. The crystallinity of the iron oxide nanoparticles is enhanced by the post annealing treatment. The particle size of the as-synthesized iron oxide nanoparticles was about 5 nm and the particle shape was almost spherical. But the particle size of the post annealed iron oxide nanoparticles at $700^{\circ}C$ was around 25 nm and the particle shape was spherical and irregular. The as-synthesized iron oxide nanoparticles showed superparamagnetic behavior, but post annealed iron oxide nanoparticles at $700^{\circ}C$ did not show superparamagnetic behavior due to the increase of particle size by post annealing treatment. The saturation of magnetization of the as-synthesized nanoparticles, post annealed nanoparticles at $500^{\circ}C$, and post annealed nanoparticles at $700^{\circ}C$ was found to be 3.7 emu/g, 6.1 emu/g, and 7.5 emu/g, respectively. The much smaller saturation magnetization value than one of bulk magnetite can be attributed to spin disorder and/or spin canting, spin pinning at the nanoparticle surface.

An update technology trend in iron oxide (酸化鐵産業의 開發動向)

  • Sohn, Jin-Gun
    • Journal of the Korean Institute of Resources Recycling
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    • v.13 no.6
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    • pp.3-8
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    • 2004
  • From the world wide globalization of iron oxide industry, the global trend in iron oxide is changed rapidly and the production of iron oxide is increasing in China, currently. Iron oxide have a broad range of applications from construction materials to medical area. Therefore, it is expected that nanoparticulate iron oxides have many applications, too. A series of interesting applications in entirely different fields are introduced.

Application of Iron Oxide as a pH-dependent Indicator for Improving the Nutritional Quality

  • Meng, Xiangpeng;Ryu, Jina;Kim, Bumsik;Ko, Sanghoon
    • Clinical Nutrition Research
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    • v.5 no.3
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    • pp.172-179
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    • 2016
  • Acid food indicators can be used as pH indicators for evaluating the quality and freshness of fermented products during the full course of distribution. Iron oxide particles are hardly suspended in water, but partially or completely agglomerated. The agglomeration degree of the iron oxide particles depends on the pH. The pH-dependent particle agglomeration or dispersion can be useful for monitoring the acidity of food. The zeta potential of iron oxide showed a decreasing trend as the pH increased from 2 to 8, while the point of zero charge (PZC) was observed around at pH 6.0-7.0. These results suggested that the size of the iron oxide particles was affected by the change in pH levels. As a result, the particle sizes of iron oxide were smaller at lower pH than at neutral pH. In addition, agglomeration of the iron oxide particles increased as the pH increased from 2 to 7. In the time-dependent aggregation test, the average particle size was 730.4 nm and 1,340.3 nm at pH 2 and 7, respectively. These properties of iron oxide particles can be used to develop an ideal acid indicator for food pH and to monitor food quality, besides a colorant or nutrient for nutrition enhancement and sensory promotion in food industry.

Flame Synthesis of Silica-Coated Iron Oxide Nanoparticles and Their Characterization

  • Jun, Kimin;Yang, Sangsun;Lee, Jeonghoon;Pikhitsa, Peter V.;Choi, Mansoo
    • Particle and aerosol research
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    • v.9 no.4
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    • pp.209-219
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    • 2013
  • We have used the modified diffusion flame burner to synthesize silica coated iron oxide nanoparticles having enhanced superparamagnetic property. Silica-encapsulated iron oxide particles were directly observed using a high resolution transmission electron microscope. From the energy dispersive X-ray spectroscopy (EDS) and zeta potential measurements, the iron oxide particles were found to be completely covered by a silica coating layer. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) measurements revealed that the iron oxide core consists of ${\gamma}-Fe_2O_3$ rather than ${\alpha}-Fe_2O_3$. Our magnetization measurements support this conclusion. Biocompatibility test of the silica-coated iron oxide nanoparticles is also conducted using the protein adsorption onto the coated particle.

An update technology trend in iron oxide (산화철산업(酸化鐵産業)의 개발동향(開發動向))

  • Sohn, Jin-Gun
    • Proceedings of the Korean Institute of Resources Recycling Conference
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    • pp.47-58
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    • 2005
  • From the world wide globalization of iron oxide industy, the global trade in iron oxide is changed rapidly and the production of iron oxide is increasing in China, currently. Iron oxide have a broad range of applications from construction materials to medical area. Therefore, it is expected that nanoparticulate iron oxides have many applications, too. There is a series of interesting applications are introduced, but in entirely different fields as they are known from conventional iron oxide.

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Effect of Batch Melting Temperature and Raw Material on Iron Redox State in Sodium Silicate Glasses

  • Mirhadi, Bahman;Mehdikhani, Behzad
    • Journal of the Korean Ceramic Society
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    • v.48 no.2
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    • pp.117-120
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    • 2011
  • In this study, the redox state of iron in sodium silicate glasses was varied by changing the melting conditions, such as the melting temperature and particle size of iron oxide. The oxidation states of the iron ion were determined by wet chemical analysis and UV-Vis spectroscopy methods. Iron commonly exists as an equilibrium mixture of ferrous ions, $Fe^{2+}$, and ferric ions $Fe^{3+}$. In this study, sodium silicate glasses containing nanoparticles of iron oxide (0.5% mol) were prepared at various temperatures. Increase of temperature led to the transformation of ferric ions to ferrous ions, and the intensity of the ferrous peak in 1050 nm increased. Nanoparticle iron oxide caused fewer ferrous ions to be formed and the $\frac{Fe^{2+}}{Fe^{3+}}$ equilibrium ratio compared to that with micro-oxide iron powder was lower.

Formation of iron oxides from acid mine drainage and magnetic separation of the heavy metals adsorbed iron oxides

  • Kwon, Hee-won;Kim, JeongJin;Ha, Dong-Woo;Kim, Young-Hun
    • Progress in Superconductivity and Cryogenics
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    • v.18 no.1
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    • pp.28-32
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    • 2016
  • There are a few thousand abandoned metal mines in South Korea. The abandoned mines cause several environmental problems including releasing acid mine drainage (AMD), which contain a very high acidity and heavy metal ions such as Fe, Cu, Cd, Pb, and As. Iron oxides can be formed from the AMD by increasing the solution pH and inducing precipitation. Current study focused on the formation of iron oxide in an AMD and used the oxide for adsorption of heavy metals. The heavy metal adsorbed iron oxide was separated with a superconducting magnet. The duration of iron oxide formation affected on the type of mineral and the degree of magnetization. The removal rate of heavy metal by the adsorption process with the formed iron oxide was highly dependent on the type of iron oxide and the solution pH. A high gradient magnetic separation (HGMS) system successfully separated the iron oxide and harmful heavy metals.

Improvement of color for iron oxide from waste pickling acid

  • Sohn, Jin-Gun;Kim, Dae-Young;Lee, Jae-Young;Lee, Hun-Ha;Kim, Jang-Su;Sung, Gee-Woong
    • Proceedings of the IEEK Conference
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    • pp.144-148
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    • 2001
  • In this study, to improve the color of iron oxide from waste pickling acid at the cold rolling mill, quality control technologies to improve color were investigated. During operation of the spray roaster, the charge amount of waste acid per hour, temperature, and numbers of spray nozzles were investigated. At the admixing process, titanium oxide, silica, and goethite were tested. The color character of iron oxide can be improved by process control of the spray roaster and the admixing process at a pigment factory. Iron oxide from this study is appropriate for use as a colorant of a concrete product.

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