• Proceedings of the Korea Association of Crystal Growth Conference
• /
• 1998.09a
• /
• pp.65-70
• /
• 1998

Fine powders of $\alpha$-Fe2O3 were prepared by precipitation method using iron (III) nitrate in ethanol solvent and the thick film using this powder was made by the screen printing technology. Effects of the reaction temperature and concentration of the iron (III) nitrate on the particle size and specific surface area were studied. Also, the relationship between the powder size and properties of the thick film was discussed.

• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.7
• /
• pp.729-734
• /
• 2008

The higher valence state of iron i.e., Fe(VI) was employed for the treatment of Cu(II)-EDTA in the aqueous/waste waters. The ferrate(VI) was prepared through wet oxidation of Fe(III) by sodium hypochlorite. The purity of prepared Fe(VI) was above 93%. The stability of Fe(VI) solution decreased as solution pH decreased through self decomposition. The reduction of Fe(VI) was obtained by using the UV-Visible measurements. The dissociation of Cu(II)-EDTA complex through oxidation of EDTA using Fe(VI) and subsequent treatment of organic matter and metal ions by Fe(III) reduced from Fe(VI) in bench-scale of continuous flow reactor were studied. The removal efficiencies of copper were 69% and 79% in pH control basin and reactor, respectively, at 120 minutes as retention time. In addition, Cu(II)-EDTA in the reactor was decomplexated more than 80% after 120 minutes as retention time. From this work, a continuous treatment process for the wastewater containing metal and EDTA by employing Fe(VI) as muluti-functional agent was developed.

• Nuclear Engineering and Technology
• /
• v.3 no.1
• /
• pp.15-19
• /
• 1971

High specific activity $^{51}$ Cr is mainly prepared by Szilard-Chalmers process from $K_2$CrO$_4$target. Usually the recoil atom, Cr* (III), is coprecipitated with Fe(III) as a scavenger to be separated from $K_2$CrO$_4$. A new preparation method has been developed, by adding 0.1N NaOH and $C_2$H$^{5}$ OH to the irradiated target solution, to precipitate Cr* (III) without any scavenger such as Fe(III). The new method gives the product of higher specific activity and better yield than that of other methods, in the shorter processing time. This method is compared with the conventional method and the French method, and following results are obtained: the new method gives specific activity more than twice that of the conventional method and better yield than the conventional method : the French method and the new method give similar specific activity, but yield of the new method is almost twice that of the French method.

• Analytical Science and Technology
• /
• v.12 no.6
• /
• pp.515-520
• /
• 1999

The spectrophotometric determination of Al(III) with thorin have been investigated. The optimum condition of pH, concentration of ligand and surfactant, and stability were evaluated. The thorin ligand offers selective separation of Al(III) from sample solution containing Fe(III), Ni(II), Cu(II), Pb(II) and Cu(II). Various surfactants were tested and Triton X-100 showed the best stability and the maximum absorbance in an aqueous solution of Al(III)-Thorin-Triton X-100 complex appears about 526 nm. The method was applied for the determination of Al(III) in mixed sample solution. Separation and preconcentration was performed with a short column filled with resorcinol-formaldehyde resin. Control of the pH during the column operation is essential because the adsorption capacities are very sensitive to change in pH. Their separation was carried out in 0.2 M acetic acid-sodium acetate buffer solution (pH 4.5) and 1.0 M $HNO_3$media.

• Journal of the Mineralogical Society of Korea
• /
• v.30 no.1
• /
• pp.21-29
• /
• 2017

Surface soils on Barton Peninsula, King George Island, West Antarctica were investigated to acquire the mineralogical and geochemical data of soil in Antarctica. Multiline of techniques for example, X-ray diffraction (XRD), transmission electron microscopy (TEM)-electron energy loss spectroscopy (EELS), and wet chemistry analysis were performed to measure the composition of clay minerals, Fe-oxidation states, cation exchange capacity, and total cation concentration. Various minerals in sediments such as smectite, illite, chlorite, kaolinite, quartz and plagioclase were identified by XRD. Fe-oxidation states of bulk soils showed 20-40% of Fe(II) which would be ascribed to the reduction of Fe in clays as well as Fe-bearing minerals. Moreover, redox states of Fe in smectite structure was a ~57% of Fe(III) consistent to the values for the bulk soils. The cation exchange capacity of bulk soils ranged from 100 to 300 meq/kg and differences were not significantly measured for the sampling locations. Total cations (Mg, K, Na, Al, Fe) of bulk soils varies, contrast to the heavy metals (Co, Ni, Cu, Zn, Mn). These results suggested that composition of bed rocks influenced the distribution of elements in soil environments and soils containing clay compositions may went through the bio/geochemical alteration.

• Resources Recycling
• /
• v.27 no.6
• /
• pp.53-58
• /
• 2018

Solvent extraction of Li(I) from weak HCl solution was investigated by the mixture of TBP/MIBK with other neutral extractants such as Cyanex 923, TOPO and TOP. The TBP/MIBK organic phase was loaded with 0.1 M $FeCl_3$ at different HCl concentrations (1-9 M). Extraction of Li(I) from weak HCl solution is related to the stability of $FeCl_3$ in the organic mixture. As HCl concentration increased in preparing the loaded TBP phase, the stripping percentage of Fe(III) during the extraction of Li(I) became reduced and thus Li(I) could be extracted by ion exchange reaction with hydrogen ion in the organic. The concentration of TBP in the extractant mixture affected the stability of $FeCl_3$. Compared to TBP, Fe(III) was easily stripped from the loaded MIBK and thus no Li(I) was extracted by the mixture with MIBK. The nature of neutral extractant with TBP/MIBK showed little difference in the extraction of Li(I) and stripping of Fe(III).

• Journal of Korean Society of Water and Wastewater
• /
• v.26 no.1
• /
• pp.77-85
• /
• 2012

The present study investigates treatment methods for removal of arsenic from wastewater. The granular activated carbon (GAC) with the coating of iron chloride ($FeCl_3$) was used for the treatment of a low concentration of arsenic from wastewater. Batch experiments were performed to investigate the synthesis of Fe-GAC (Iron coated granular activated carbon), effects of pH, adsorption kinetics and the Langmuir model. The synthesized Fe-GAC with 0.1 M $FeCl_3$ shows best removal efficiency. Adsorption studies were carried out in the optimum pH range of 4-6 for arsenic removal. The Fe-GAC showed promising results by removing 99.4% of arsenic. In the adsorption isotherm studies, the observed data fitted well with the Langmuir models. In continuous column study showed that As(V) could be removed to below 0.25 mg/L within 1,020 pore volume. Our results suggest that the surface modified granular activated carbon treated with $FeCl_3$ for effective removal of arsenic from wastewater.

• Applied Chemistry for Engineering
• /
• v.5 no.2
• /
• pp.238-246
• /
• 1994

Partial oxidation of cyclohexane by HOOH was carried out with the transition metal complexes composed of Fe(II) or Fe(III)/picolinic acid derivatives. The major products were turned out to be cyclohexanone and cyclohexanol wlth the one/ol ratios of 3~10. The best performance was observed in a mixed solvent of pyridine/acetic acid(volume ratio 2.5:1, pH 5.3) and optimal temperature was $25{\sim}40^{\circ}C$. It was known that cyclohexyl hydroperoxide is the reaction intermediate, and that the reaction dominantly follows non-radical pathways which was ascertained from the results of the adamantane oxidation and radical trap experiments.

• Journal of the Mineralogical Society of Korea
• /
• v.32 no.1
• /
• pp.63-69
• /
• 2019

The oxidation states of structural Fe in minerals reflect the paleo-depositional redox conditions for the biologically or abiotically induced mineral formation. Particularly, nano-scale analysis using high-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS) is necessary to identify evidence for the microbial role in the biomineralization. HRTEM-EELS analysis of oxidation states of structural Fe and carbon bonding structure differentiate biological factors in mineralization by mapping the distribution of Fe(II)/Fe(III) and source of organic C. HRTEM-EELS technique provides geomicrobiologists with the direct nano-scale evidence of microbe-mineral interaction.

• Journal of the Korean Chemical Society
• /
• v.68 no.2
• /
• pp.82-86
• /
• 2024

This paper presents the solid-state synthesis of insoluble Prussian blue (Fe₄[Fe(CN)₆]₃·xH₂O, PB) in a ball mill, utilizing the fundamental components of PB. Solid-state synthesis offers several advantages, such as being solvent-free, quantitative, and easily scalable for industrial production. Traditionally, the solid-state synthesis of PB has been limited to the reaction between iron(II/III) ions and hexacyanoferrate(II/III) complex ions, essentially an extension of the solution-based coprecipitation method to solid-state reaction. Taking a bottom-up approach, a reaction is designed where the reactants consist of the basic building blocks of PB: Fe²⁺ ions and CN^- ions. The reaction, with a molar ratio of Fe²⁺ and CN^- corresponding to 1:2.8, yields PB, while a ratio of 1:6.6 results in a mixture of potassium hexacyanoferrate(II) (K₄Fe(CN)₆), potassium chloride (KCl), and potassium cyanide (KCN). This synthetic approach holds promise for environmentally friendly methods to synthesize multimetallic PB with maximum entropy in nearly quantitative yield.