• 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.

• Corrosion Science and Technology
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• v.16 no.4
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• pp.187-193
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• 2017

Polymer amines are found to show distinct corrosion inhibition effects in acidic media. The functional groups of organic compounds have a wide role in the physical and chemical properties, for the inhibition efficiency with respect to steric factors, aromaticity, and electron density. The influence of $H^+$ ions and $Cl^-$ ions on the corrosion inhibitive effect of poly(p-aminophenol) for iron in hydrochloric acid was studied using electrochemical methods such as impedance, linear polarization, and Tafel polarization techniques. The experiments were conducted with and without the inhibitor, poly(p-aminophenol). The concentration range of $H^+$ ions and $Cl^-$ ions are from 1 M to 0.05 M and 1 M to 0.1 M, respectively. With the inhibitor poly(p-aminophenol), this study shows that inhibition efficiency decreases with the reduction of $H^+$ ion and $Cl^-$ ion concentrations in aqueous solution. Further, it reveals that the adsorption of an inhibitor on the surface of iron is dependent on the concentrations of $H^+$ and $Cl^-$ ions in the solution and the adsorption of inhibitor on the iron surface through the cationic form of amine.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2577-2583
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• 2009

Presented are the formation of iron oxide layers on evaporator tubes in an actual fossil power plant operated under all volatile treatment (AVT) condition and an experimental simulation of iron oxide formation in the presence of ferrous and ferric ions. After actual operations for 12781 and 36326 hr in the power plant, two iron oxide layers of magnetite on the evaporator tubes were found: a continuous inner layer and a porous outer layer. The experimental simulation (i.e., artificial corrosion in the presence of ferrous and ferric ions at 100 ppm level for 100 hr) reveals that ferrous ions turn the continuous inner oxide layer on tube metal to cracks and pores, while ferric ions facilitate the production of porous outer oxide layer consisting of large crystallites. Based on a comparison of the oxide layers produced in the experimental simulation with those observed on the actually used tubes, we propose possible routes for oxid layer formation schematically. In addition, the limits of the proposed corrosion routes are discussed in detail.

• Journal of Industrial Technology
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• v.32 no.A
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• pp.21-27
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• 2012

The characteristics of floc formation of the iron(Fe) ions contained in the acid mine drainage was studied for developing the process treating the acid mine drainage. The iron(Fe) ions were formed into flocs by the acid-base reaction with the added $Ca(OH)_2$. The molal ratio of iron(Fe) vs $Ca(OH)_2$ was one of major control variables in treatment; pH change, iron(Fe) ions concentration in treated drainage, DO (dissolved oxygen content). In addition, the air gave much effect on the color of the $iron(Fe)-Ca(OH)_2$ flocs and the attachment to magnet. The attaching to the magnet of the flocs formed in the air was much less than the case without air.

• Journal of Industrial Technology
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• v.33 no.A
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• pp.89-92
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• 2013

The characteristics of floc formation of the iron(Fe) ions was studied for developing the process treating the acid mine drainage. The metal ions in aqueous solution oxidized with oxygen in air, which generated hydrogen ion and lowered the pH of the aqueous solution. The iron(Fe) ions were formed into flocs by the acid-base reaction with the added $Ca(OH)_2$ for the neutralizing the solution. There were several variables affecting the formation, size and color of floc; whether air was present or not, air feeding rate, oxidizing time, concentration of $Ca(OH)_2$, the acid-base reaction time of the $iron(Fe)-Ca(OH)_2$. For proper formation of the $iron(Fe)-Ca(OH)_2$ flocs and developing the floc treating system, the control variables mentioned above should be considered.

• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.90-95
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• 2022

In the present work, biochar was prepared using Achyanthes japonica stem as a by-product of herbal medicine. In order to apply the prepared biochar to water treatment process, the adsorption characteristics of zinc and iron ions dissolved in water were investigated. When the experiments were performed for 2 h to remove 70 and 100 mg/L of zinc ions, the adsorption amounts of 32.3 and 31.0 mg/g were obtained, respectively. It was also found that the adsorption amount of Achyanthes japonica stem biochar for the removal process of zinc ion was three times higher than that of the activated carbon. In addition, when the experiments were performed for 2 h to treat 70 and 100 mg/L of iron ions, high adsorption amounts of 50.1 and 54.3 mg/g were achieved, respectively. In order to further enhance the removal efficiency of zinc and iron ions, a steam activation process was performed on the biochar of Achyanthes japonica stem. As a result, the removal efficiencies of 70 and 100 mg/L of zinc ions increased to 80 and 60%, respectively. Also, the removal efficiencies of 70 and 100 mg/L of iron ions were improved to 100 and 82%, respectively. In addition, when the biochar of Achyanthes japonica stem with a steam activation was compared with the untreated biochar of Achyanthes japonica stem, the specific surface area increased 37.3 times, and the total and macroporpous pore volumes were improved by 28.4 and 136 times, respectively. Therefore, the results can be used for economically and practically adsorbing zinc and iron ions contained in water.

• Animal cells and systems
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• v.14 no.4
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• pp.245-252
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• 2010

Iron uptake in mitochondria and fractionated mitochondria compartments was studied to understand iron transport in heart mitochondria. The inner membrane is most active in iron uptake. Mitochondrial uptake was dependent on iron concentration and the amount of mitochondria. Iron transport was inversely proportional to pH in the range of 6.0 to 8.0. Iron transport reached a maximum after 30 min of incubation at $37^{\circ}C$. Iron uptake was inhibited by 1 mM ATP and stimulated by 1 mM ADP. The oxidative phosphorylation inhibitor oligomycin inhibited iron uptake, but rotenone and antimycin A did not. The divalent ions $Mg^{2+}$, $Cu^{2+}$, $Mn^{2+}$, and $Zn^{2+}$ suppressed iron uptake at $10\;{\mu}M$ and stimulated it at 1 mM. The divalent ion $Ca^{2+}$ stimulated iron uptake at $10\;{\mu}M$ and suppressed it at 1 mM, competing with iron. The uptake of calcium was stimulated by 10 to $1000\;{\mu}M$ ATP, while iron uptake was stimulated reciprocally by 10 to $1000\;{\mu}M$ ADP, suggesting that these ions have movements similar to those of ATP and ADP.

• Journal of the Korean Chemical Society
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• v.68 no.1
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• pp.20-24
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• 2024

This article presents the advantages of utilizing gossypol and its derivatives as reagents for iron (III) (Fe (III)) ions. A novel spectrophotometric method has been developed for the determination of Fe (III) using gossypol derivatives in the presence of a universal buffer solution. Optimal conditions have been identified, and the composition and stability constants of the Fe (III) complex with gossypolacetic acid have been determined.

• Journal of the Korean institute of surface engineering
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• v.40 no.1
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• pp.44-56
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• 2007

Excavated archaeological iron artifacts are usually conducted the conservation treatment for removal of chloride ions in the corrosion products. However, some iron artifacts are corroded again even after the conservation treatment due to unremoved chloride ions. Therefore, it is important to prevent desalinized artifacts from the occurrence of corrosion after the treatment. In this paper, we investigated the characteristics of corrosion products on salinized iron artifacts and evaluated the variety of desalination methods such as autoclave, intensive washing and NaOH. It was also found that ${\beta}-FeOOH$ (Akaganeite) played an important role on the occurrence of corrosion and the treatment for removal of chloride ions. The extents of desalination were compared between the desalination methods. Results showed that the autoclave method represented the highest efficiency for desalination while the intensive washing method was the lowest.

• International Journal of Advanced Culture Technology
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• v.8 no.2
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• pp.283-288
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• 2020

This study investigated the purification process of groundwater contaminated with zinc and arsenic using a permeable reactive barrier with a zero-valent iron/pumice mixture. We determined the removal rates of the contaminants for 30 days. In this study, column reactor filled with the zero-valent iron/pumice reactive mixture was used. Experimental results showed that the mixture exhibited an almost complete removal of the zinc and arsenic ions. Arsenic was removed via co-precipitation and adsorption processes while zinc ions were asorbed in active sites.The purification process of water from the metal ionscontinued for 30 days with constant hydraulic conductivity because of the enhanced porosity of the pumice and interparticle distance between the zero-valent iron and pumice. Contaminants removal rates and the remediation mechanism for each reactive system are described in this paper.