본 연구에서는 비소(arsenic, As) 제거 특성을 가진 망간-철 산화물(manganese-iron oxide, MF)을 제조하고, 이를 poly vinylidene fluoride (PVdF)와 복합화를 진행하여 As(III)와 As(V)를 동시에 제거가 가능한 수처리용 나노섬유복합막 (polymer nanofiber membrane with Mn-Fe, PMF) 제조에 관한 기초 연구를 진행하였다. Transmission electron microscope (TEM) 분석을 통해 MF 소재의 형상 및 구조를 확인하였으며, PMF 복합막의 수처리용 분리막으로의 활용가능성을 조사하 기 위하여 기계적 강도, 기공크기, 접촉각 및 수투과도 분석을 진행하였다. 측정결과로부터 망간과 철 비율이 같은 PMF11 복 합막의 기계적 강도가 가장 높은 결과값(232.7 kgf/cm2)을 나타낸 것을 확인할 수 있었다. 또한, MF 소재의 도입에 따라 기공 크기가 점차 줄어드는 경향성을 확인할 수 있었으며, 특히, 철 산화물의 조성비가 증가할수록 기공크기가 감소하는 경향성을 보여주었다. 수투과도 측정결과 MF 소재의 도입에 따라 PVdF 나노섬유막에 비해 약 10~60% 이상 향상되는 결과를 나타내 었다. 제조된 MF 소재 및 PMF 복합막의 비소 제거 특성평가를 통해 As(III)와 (V)의 동시 제거 가능하며, 특히, MF01 샘플 의 경우 As(III)와 (V)에 각각 93, 68%의 가장 높은 흡착제거율을 나타내었다. 따라서 본 연구에서는 제조된 MF소재 및 PMF 복합막을 통해 수처리용 분리막의 기능성 향상을 위한 기초연구 자료로 활용할 수 있을 것으로 기대된다.

Fabrication of iron oxide/carbon nanotube composite structures for detection of ammonia gas at room temperature is reported. The iron oxide/carbon nanotube composite structures are fabricated by in situ co-arc-discharge method using a graphite source with varying numbers of iron wires inserted. The composite structures reveal higher response signals at room temperature than at high temperatures. As the number of iron wires inserted increased, the volume of carbon nanotubes and iron nanoparticles produced increased. The oxidation condition of the composite structures varied the carbon nanotube/iron oxide ratio in the structure and, consequently, the resistance of the structures and, finally, the ammonia gas sensing performance. The highest sensor performance was realized with 500 oC/2 h oxidation heat-treatment condition, in which most of the carbon nanotubes were removed from the composite and iron oxide played the main role of ammonia sensing. The response signal level was 62% at room temperature. We also found that UV irradiation enhances the sensing response with reduced recovery time.

This study was carried out for characterization of MIO synthesized in our laboratory by co-precipitation method and applied isotherm and kinetic models for adsorption properties. XRD analysis were conducted to find crystal structure of synthesized MIO. Further SEM and XPS analysis was performed before and after phosphate adsorption, and BET analysis for surface characterization. Phosphate stock solution was prepared by KH2PO4 for characterization of phosphate adsorption, and batch experiment was conducted using 50 ml conical tube. Langmuir and Freundlich models were applied based on adsorption equilibrium test of MIO by initial phosphate solution. Pseudo first order and pseudo second order models were applied for interpretation of kinetic model by temperature. Surface area and pore size of MIO were found 89.6 m2/g and 16 nm respectively. And, the determination coefficient (R2) value of Langmuir model was 0.9779, which was comparatively higher than that of Freundlich isotherm model 0.9340.

식용수의 비소오염으로 인한 피해로 비소에 대한 관심이 증대되고 있으며, 아시아 지역뿐만 아니라 북남미, 유럽까지 비소로 오염된 지하수가 발견되고 있다. 본 연구에서는 As(Ⅲ)와 As(V)의 흡착특성을 가진 것으로 알려진 망간-철 산화물을 합성하고, PVdF고분자를 이용하여 복합나노섬유를 제조하였으며, 복합막의 물리적 특성과 비소제거 성능을 확인하였다. 복합화 전 합성된 망간-철 산화물을 ICP를 이용하여 비소제거율을 측정한 결과 As(V)는 43.6%, As(Ⅲ)는 65.5%의 제거율을 보였다.

In this study, the reduction kinetics and behaviors of oxides in the water-atomized iron powder have been evaluated as a function of temperature ranging 850-1000˚C in hydrogen environment, and compared to the reduction behaviors of individual iron oxides including Fe2O3, Fe3O4 and FeO. The water-atomized iron powder contained a significant amount of iron oxides, mainly Fe3O4 and FeO, which were formed as a partially-continuous surface layer and an inner inclusion. During hydrogen reduction, a significant weight loss in the iron powder occurred in the initial stage of 10 min by the reduction of surface oxides, and then further reduction underwent slowly with increasing time. A higher temperature in the hydrogen reduction promoted a high purity of iron powder, but no significant change in the reduction occurred above 950˚C. Sequence reduction process by an alternating environment of hydrogen and inert gases effectively removed the oxide scale in the iron powder, which lowered reduction temperature and/or shortened reduction time.

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 150μm in the glaze, and the densest band of magnesium oxide was found 50 to 100μm 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.

The iron oxides nanoparticles and iron oxide with other compounds are of importance in fields including biomedicine, clinical and bio-sensing applications, corrosion resistance, and magnetic properties of materials, catalyst, and geochemical processes etc. In this work we describe the preparation and investigation of the properties of coated magnetic nanoparticles consisting of the iron oxide core and organic modification of the residue. These fine iron oxide nanoparticles were prepared in air environment by the co-precipitation method using of Fe2+ : Fe3+ where chemical pre- cipitation was achieved by adding ammonia aqueous solution with vigorous stirring. During the synthesis of nanoparti- cles with a narrow size distribution, the techniques of separation and powdering of nanoparticles into rather monodisperse fractions are observed. This is done using controlled precipitation of particles from surfactant stabilized solutions in the form organic components. It is desirable to maintain the particle size within pH range, temperature, solution ratio wherein the particle growth is held at a minimum. The iron oxide nanoparticles can be well dispersed in an aqueous solution were prepared by the mentioned co-precipitation method. Besides the iron oxide nanowires were prepared by using similar method. These iron oxide nanoparticles and nanowires have controlled average size and the obtained products were investigated by X-ray diffraction, FESEM and other methods.

In this work, iron oxide (Fe3O4) nanoparticles were deposited on multi-walled carbon nanotubes (MWNTs) by a simple chemical coprecipitation method and Fe3O4-decorated MWNTs (Fe-MWNTs)/polypyrrole (PPy) nanocomposites (Fe-MWNTs/PPy) were prepared by oxidation polymerization. The effect of the PPy on the electrochemical properties of the Fe-MWNTs was investigated. The structures characteristics and surface properties of MWNTs, Fe-MWNTs, and Fe-MWNTs/PPy were characterized by X-ray diffraction and X-ray photoelectron spectroscopy, respectively. The electrochemical performances of MWNTs, Fe-MWNTs, and Fe-MWNTs/PPy were determined by cyclic voltammetry and galvanostatic charge/discharge characteristics in a 1.0 M sodium sulfite electrolyte. The results showed that the Fe-MWNTs/PPy electrode had typical pseudo-capacitive behavior and a specific capacitance significantly greater than that of the Fe-MWNT electrode, indicating an enhanced electrochemical performance of the Fe-MWNTs/PPy due to their high electrical properties.

The chemical formula of magnetite (Fe3O4) is FeO·Fe2O3, t magnetite being composed of divalent ferrous ion andtrivalent ferric ion. In this study, the influence of the coexistence of ferrous and ferric ion on the formation of iron oxide wasinvestigated. The effect of the co-precipitation parameters (equivalent ratio and reaction temperature) on the formation of ironoxide was investigated using ferric sulfate, ferrous sulfate and ammonia. The equivalent ratio was varied from 0.1 to 3.0 andthe reaction temperature was varied from 25 to 75. The concentration of the three starting solutions was 0.01mole. Jarosite wasformed when equivalent ratios were 0.1-0.25 and jarosite, goethite, magnetite were formed when equivalent ratios were 0.25-0.6. Single-phase magnetite was formed when the equivalent ratio was above 0.65. The crystallite size and median particle sizeof the magnetite decreased when the equivalent ratio was increased from 0.65 to 3.0. However, the crystallite size and medianparticle size of the magnetite increased when the reaction temperature was increased from 25oC to 75oC. When ferric and ferroussulfates were used together, the synthetic conditions to get single phase magnetite became simpler than when ferrous sulfatewas used alone because of the co-existence of Fe2+ and Fe3+ in the solution.

A nanocomposite consisting of Fe3O4 and MWCNT was produced via sol-gel technique using FeCl3 along with MWCNT by calcination at 300℃. The degradation effect of rhodamine B dye has been investigated under UV illumination in a darkroom. The degradation reaction was studied by monitoring the discoloration of dye as a function of irradiation time using UV-visible spectrophotometeric technique. The Fe3O4-MWCNT samples have continuous degradation ability under the UV illumination with the first order kinetics and the dye removal was better than in the pristine Fe3O4. The resultant composite catalyst was found to be efficient for the photo-Fenton reaction of the dye.

A Fe(OH)2 suspension was prepared by mixing iron sulfate and a weak alkali ammonia solution. Following this, iron oxides were synthesized by passing pure oxygen through the suspension (oxidation). The effects of different reaction temperatures (30˚C, 50˚C, 70˚C) and equivalent ratios (0.1~10.0) on the formation of iron oxides were investigated. An equilibrium phase diagram was established by quantitative phase analysis of the iron oxides using the Rietveld method. The equilibrium phase diagram showed a large difference from the equilibrium phase diagram of Kiyama when the equivalent ratio was above 1, and single Fe3O4 phase only formed above an equivalent ratio 2 at all reaction temperatures. Kiyama synthesized iron oxide using iron sulfate and a strong alkali NaOH solution.

The effects of reaction temperature and precursor concentration on the microstructure and magnetic properties of nanoparticles synthesized as final products of iron acetylacetonate in chemical vapor condensation (CVC) were investigated. Pure phase was obtained at temperature above and crystallite size of nanoparticles decreased with lowering precursor concentration. Also, the coercivity decreases with decreasing crystallite size of nanopowder. The lowest coercivity was 7.8 Oe, which was obtained from the nanopowder sample synthesized at precursor concentration of 0.3M. Then, the crystallite size of nanoparticles was 8.8 nm.

Nitric oxide (NO) has been known to inf1uence cell fate through apoptotic or necrotic cell death. Here, we investigated the role of nitric oxide on the growth and viability of immortalized human salivary gland (HSG) cells 띠 vitro. Treatrnent of HSG with a NO donor, S-nitroso-N-acetyl-DL-penκi1lamine (SNAP), significantly diminished the growth rate of HSG in a concentration dependent manner. However, this retardation of cell비ar growth rate was not corresponded to the apoptotic cell death of HSG cells, because there were no characteristic apopto디c features such as condensation of nuclear chromatin, nuclear fragmentation, and the apoptotic peak of propidium iodide (PI)-stained nuclei by flow cytome띠. 까ùs implies that HSG cells are resistant to NO-mediated 다π。to:잉city. 1n SNAP treated HSG cells, cell cycle analysis revealed that the number of G2/M phase increased markedly, according to while the percentage of cells in GO/Gl and S phases was not significantly affected. Otherwise, high concentrations of SNAP increased both P1 and annexin V positive cells. 1nterestingly, preincubation of HSG cells with iron chelator, deferoxamine (DFO), significantly diminished NO cytotoxicity more than when HSG cells are only incubated with SNAP which su잃.ests the role of iron homeostasis in NO-mediated cell death of HSG cells. 1n addi디。n ， treatrnent of HSG cells with SNAP specifically cleaved iron regulatory protein-2 (IRP2) while not affecting 1RP1. Collectively, the mπent results s멍gest that NO has a potential to control HSG cell growth through cell cycle arresting at G2/M phase. 1n addi디on ， intracellular iron homeostasis nùght play an important role in regulating cell survival of HSG cells

Nanoparticles of iron oxides have been prepared by the levitational gas condensation (LGC) method, and their structural and magnetic properties were studied by XRD, TEM and Mossbauer spectroscopy. Fe clusters were evaporated from a surface of the levitated liquid Fe droplet and then condensed into nanoparticles of iron oxide with particle size of 14 to 30 nm in a chamber filled with mixtures of Ar and gases. It was found that the phase transition from both - and -Fe to , which was evaluated from the results of Mossbauer spectra, strongly depended on the flow rate. As a result, - was synthesized under the flow rate of 0.1(Vmin)0.15, whereas was synthesized under the , flow rate of 0.15(Vmin)0.2.

결정 성장 조절체를 이용하여 수용액 중에서 직접 α산화철을 제조하였으며, 염기도에 따른 생성물의 입자 특성과 반응기구, α산화철의 생성 과정과 침상형 입자의 생성 반응 기구를 고찰하였다. pH 9.0이하에서는 hexagonalgudxo, pH 10.75-11.75범위에서는 ellipsoidal 또는 rectangular 형태의 α-Fe2O3입자로 각각 생성되었으며, pH12.50이상에서는 acicular 형태의 α-FeOOH입자가 생성되었다. pH 10.75-11.75범위에서 제조된 생성물의 염기도는 결정 성장 조절제의 해리에 의해 생성된 수산기 이온(OH-) 때문에 반응물의 염기도에 대비해 약간 증가하는 현상을 나타내었다. 결정 성장 조절제로 사용한 구연상은 제이철 수산화물에 구연산 음이온(R-COO-) 형태로 흡착되어 생성물인 α산화철의 입자 형태를 침상 형태로 유도하였다.

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 181.3 m2/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.

금속나노입자는 진단이나 치료를 포함한 의생명응용분야에 있어 매력적인 특징들을 갖고 있다. 양성자 빔 치료를 위한 방사선증감제로 사용하기 위해 가교덱스트란이 코팅된 산화철나노입자(SPIONs)와 실리카가 코팅된 산화가돌리늄나노입자(SPGONs)를 합성하였다. 덱스트란과 실리카는 각각 SPIONs와 SPGONs의 보호수단이다. 합성된 SPIONs와 SPGONs를 투과전자현미경(TEM)으로 분석한 결과 각각 평균 직경이 3~5 nm와 30~100 nm였다. 합성된 방사선 증감제의 효과를 평가하기 위해 세포생존곡선 측정과 Western blotting을 수행하였다. 측정된 세포생존곡선으로부터 계산된 90% 세포사멸 시 방사선증감비는 SPIONs와 SPGONs에 대하여 각각 1.23과 1.03이었다. Western blotting 결과 역시 Cytochrome C의 발현량이 SPIONs를 처리한 암세포에서 유의적으로 증가됨을 보였다.