• Korean Journal of Soil Science and Fertilizer
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• v.15 no.3
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• pp.162-165
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• 1982

As an approach to the explanation of increased availability of phosphate in reduced wetland soils, the interrelationships among pH, pe, $Fe^{+{+}}$ and water soluble phosphate in reduced soil-water suspension was studied. 1. p.e value of soil incubated for 8 weeks at $30^{\circ}C$ under waterlogged condition was sufficiently low to allow the conversion of strengite to vivianite. 2. The concentration of water soluble $Fe^{+{+}}$ in this system was higher than that is allowable by the solubility of vivianite. 3. From the relationship between pH and the concentration of water soluble $Fe^{+{+}}$, the concentration of water soluble $Fe^{+{+}}$ could be determined with the solubility of $FeCO_3$. 4. No definite relationship between pH and water soluble P was recognized which implied that the concentration of water soluble P in this system could not determined with the solubility of vivianite.

• Membrane and Water Treatment
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• v.11 no.3
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• pp.207-215
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• 2020

Vivianite (Fe₃²⁺(PO₄)2·8H₂O) and green rust ([Fe₄²⁺Fe₂³⁺(OH)^-₁₂][SO₄^2-·2H₂O]^2-), ferrous containing minerals, could remove aqueous U(VI) in 5 min. and the efficiencies of green rust were roughly 2 times higher than that of vivianite. The zeta potential measurement results implies that the better performance of green rust might be attributed to the favorable surface charge toward uranyl phosphate species. The removal behaviors of the minerals were well fitted by pseudo-second order kinetic model (R² > 0.990) indicating the dominant removal process was chemical adsorption. Effects of Ca²⁺ and CO₃^2- at pH 7 were examined in terms of removal kinetic and capacity. The kinetic constants of aqueous U(VI) were 8 and 13 times lower (0.492 × 10^-3 g/(mg·min); 0.305 × 10^-3 g/(mg·min)) compared to the value in the absence of the ions. The thermodynamic equilibrium calculation showed that the stable uranyl species (uranyl tri-carbonate) were newly formed at the condition. Surface investigation on the reacted mineral with uranyl phosphates species were carried out by XPS. Ferrous iron and U(VI) on the green rust surface were completely oxidized and reduced into Fe(III) and U(IV) after 7 d. It suggests that the ferrous minerals can retard U(VI) migration in phosphate-rich groundwater through the adsorption and subsequent reduction processes.

• Advances in environmental research
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• v.4 no.2
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• pp.135-142
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• 2015

In this study, we evaluated the adsorption/desorption of uranium (U) in pure soil environment using continuous column reactor. We additionally investigated the adsorption/desorption mechanism of U on vivianite surface in molecular scale using quantum calculation. We observed that below $0.1{\mu}M$ of U was detected after 20 d from U injection ($1{\mu}M$) in adsorption test. However, all of absorbed U was detached from vivianite surface in 24 h by injection of CARB solution ($1.44{\times}10^{-2}M\;NaHCO_3$ and $2.8{\times}10^{-3}M\;Na_2CO_3$). Based on exchange energy calculation, we found that $UO_2(CO_3)_2{^{2-}}$ and $UO_2(CO_3)_3{^{4-}}$ species have higher repulsive energy than $UO_2(OH)_2$ species. The results obtained from this study could be applied to predict the behavior of uranium in contaminated and remediation sites.

• Conservation Science in Museum
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• v.7
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• pp.25-31
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• 2006

We performed the conservation treatment for Bigyeokchinjeonnoe (A kind of time bomb in the Joseon Dynasty) excavated from Hwawangsanseong Fortress in Changnyeong-gun, Gyeongsangnam-do Province. Part of the Bigyeokchinjeonnoe has been lost; we did not restore the lost part so that one can observe the inside through it. The results of X-ray investigation and C. T (Computed Tomography) scan proved the generation of many blowholes around the molding line during the casting process; a hole in the casting mold to maintain inner mold during casting was identified on the surface and traces of fortifying this part with iron plate were also identified. The main ingredients of the blue corrosion on the surface were identified as O, Fe, P, Si and Al by SEM/EDS analysis. The result of XRD analysis identified the blue corrosion as vivianite [Fe₃(PO₄)₂·8H₂O]. The metal structure clarified its material was gray cast iron.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.236-236
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• 2003

Anaerobic Fe(III)-reducing bacteria are known to be able to reduce crystalline and amorphous Fe(III) oxides. Anaerobic Fe(III)-reducing bacterial reduction can induce several kinds of secondary minerals (Fe(II) containing minerals) such as magnetite, siderite, vivianite [($Fe_{3}(PO_{4}{\cdot}2H_{2}O$], and iron sulfide (FeS) according to variety of geochemical and biological conditions. (omitted)

• Conservation Science in Museum
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• v.4
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• pp.23-32
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• 2003

As the kettle excavated from a site in Hwangnam-dong, Gyeongju was presumed to have been used as a melting crucible in a glass production workplace, we decided to prove its usage by scientific analysis. First, we performed conservation treatment to find the original status of the kettle, and then SEM-EDS and XRD analysis of the five corrosions created on the surface of the kettle. The fragment of the spout, which played a crucial role for the kettle to be considered as a melting crucible, was discovered during the conservation treatment. So the mouth rim of the kettle was restored to perfection. When we observed the microstructure of the metal sample, it was proved to be cast iron gradually cooled without heat treatment. In the corrosion products, the main components were Fe and O and other components such as P, Si, Ca, and S were found. The main compounds were quartz, vivianite, goetheite, akaganite, lepidocrocite, hematite, etc. Although these components were used as raw materials for making glass, these were found not in the melting status but mere raw materials. This can be an evidence to show these site where the kettle was excavated had been a glass production workplace. However, it is not sure that the kettle was used as a melting crucible. Moreover, if we consider the organic mold and sand clay accumulated in the well site when the kettle was excavated at first, we can see this as a formative factor of the corrosions of the kettle. Therefore, we concluded that the kettle is a typical cast iron and was not used as a melting crucible of glass.

• Korean Journal of Soil Science and Fertilizer
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• v.15 no.2
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• pp.89-94
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• 1982

1. Solubility diagram was used to estimate Chemical form of the Soil phosphates which supply phosphorus into soil solutions under submerged condition with soils originated from granite and basalt rocks. The granite origin soils with different amounts of available phosphorus have no effect of phosphate application on rice yield, while the basalt origin soil has the big effect. 2. Almost same pattern of change in pH and concentrations of phosphorus and cations in the soil solutions during the submerging period was. shown. Almost no difference in the values was recognized between NPK and NK treatments of the granite origin soils, but the difference of the basalt origin soil was recognized. 3. it was estimated from solubility diagram that phosphorus concentration in the soil solutions was governed by phosphate applied and variscite in the soils for the early stage of submerging period, and then it became to be governed by vivianite in the soils.

• Journal of the Mineralogical Society of Korea
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• v.15 no.3
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• pp.231-240
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• 2002

Microbial metal reduction influences the biogeochemical cycles of carbon and metals as well as plays an important role in the bioremediation of metals, radionuclides, and organic contaminants. The use of bacteria to facilitate the production of magnetite nanoparticles and the formation of carbonate minerals may provide new biotechnological processes for material synthesis and carbon sequestration. Metal-reducing bacteria were isolated from a variety of extreme environments, such as deep terrestrial subsurface, deep marine sediments, water near Hydrothemal vents, and alkaline ponds. Metal-reducing bacteria isolated from diverse extreme environments were able to reduce Fe(III), Mn(IV), Cr(VI), Co(III), and U(VI) using short chain fatty acids and/or hydrogen as the electron donors. These bacteria exhibited diverse mineral precipitation capabilities including the formation of magnetite ($Fe_3$$O_4$), siderite ($FeCO_3$), calcite ($CaCO_3$), rhodochrosite ($MnCO_3$), vivianite [$Fe_3$($PO_4$)$_2$ .$8H_2$O], and uraninite ($UO_2$). Geochemical and environmental factors such as atmospheres, chemical milieu, and species of bacteria affected the extent of Fe(III)-reduction as well as the mineralogy and morphology of the crystalline iron mineral phases. Thermophilic bacteria use amorphous Fe(III)-oxyhydroxide plus metals (Co, Cr, Ni) as an electron acceptor and organic carbon as an electron donor to synthesize metal-substituted magnetite. Metal reducing bacteria were capable of $CO_2$conversion Into sparingly soluble carbonate minerals, such as siderite and calcite using amorphous Fe(III)-oxyhydroxide or metal-rich fly ash. These results indicate that microbial Fe(III)-reduction may not only play important roles in iron and carbon biogeochemistry in natural environments, but also be potentially useful f3r the synthesis of submicron-sized ferromagnetic materials.