• Analytical Science and Technology
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• v.23 no.6
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• pp.560-565
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• 2010

Perchlorate ion ($ClO_4^-$) has been widely used as oxidizing agent in military weapon system such as rocket and missile fuel propellant. So it has been challenging to remove the pollutant of perchlorate ion. nanoscale zero valence iron (nZVI) particles are widely employing reduction catalyst for decomposition of perchlorate ion. nZVI particles has increasingly been utilized in groundwater purification and waste water treatment. But it have strong tendency of aggregation, rapid sedimentation and limited mobility. In this study, we focused on reduction of perchlorate ion using nZVI particles immobilized in alginate polymer bead for stabilization. The stabilized nZVI particles displayed much greater surface area, and much faster reaction rates of reduction of perchlorate ion. In this study, an efficient way to immobilize nZVI particles in a support material, alginate bead, was developed by using $Ca^{2+}$ as the cross-linking cations. The efficiency and reusability of the immobilized Fe-alginate beads on the reduction of perchlorate was tested at various temperature conditions.

• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.539-546
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• 2006

A study on the polymerization of polyethylenedioxythiophene (PEDOT) and the carbonization process of a separator was carred out in order to apply conductive polymer PEDOT to the winding typed aluminum condenser as a solid electrolyte and a negative electrode. PEDOT was polymerized with ethylenedioxythiophene (EDOT) as a monomer and ferric-p-toluenesulfonate as an oxidizing agent. The separator of condenser element was carbonized to control its fibrous tissue for the purpose of making it easy to impregnate the PEDOT solution into the microporous etched pit of aluminum foil by preventing separator from concentrating the PEDOT solution on itself. The characteristics of condenser such as capacitance, dissipation factor, equivalent series resistance, and thermal resistance depended on a carbonization temperature and a carbonization time. It was found that a thickness and a density of the used separator were major parameters of carbonization process and the characteristics of condenser were affected by these parameters.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.3
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• pp.90-96
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• 2018

This study investigated the manufacturing process and characteristics of $BKNO_3$ (Boron Potassium Nitrate) as a pyrotechnic propellant that is commonly used in the aerospace, defense, and automobile industries. The solid mixture was composed of oxidizing agent, fuel, and binder. Evaporation process was used to uniformly mix the raw materials. The optimal ratio of composition was designed through the CEA program analysis of the material characteristics and thermal responses. Further the size, shape, sensitivity, and calorimetry characteristics were studied.

• Polymer(Korea)
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• v.24 no.5
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• pp.673-681
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• 2000

Electrically conductive composites have been prepared by treating fabrics with oxidizing agent and exposing them to aniline, which deposited a substantial amount of conductive polymer within the interstices of the material. However the conductivity of the composite fabrics was limited by the irregular deposition of the conductive polymer layer. To improve the conductivity of polyaniline/nylon 6 composite fabrics, we modified the surface characteristics of nylon 6 fabrics by various plasma treatments and increased diffusion and adsorption of aniline by ultrasonic treatments. By the oxygen plasma treatment, attachment of functional groups such as C-O and C-OH increased on the surface of nylon 6 fiber, which promoted adhesion to polyaniline resulting in the higher add-on and electrical conductivity. Electrical conductivities of polyaniline/nylon 6 composite fabrics were highly increased by ultrasonic treatment, which assisted the diffusion of aniline into the inside of nylon fabrics by cavitation and vibration. Also, the effects of monomer concentration and the number of deposition cycles on the nylon 6 fabric conductivity Were investigated. As a result, the fabric conductivity increased with the monomer concentration and the number of polymerization deposition cycles.

• YAKHAK HOEJI
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• v.53 no.3
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• pp.130-137
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• 2009

In this study, isolation of antioxidative compounds was performed for development of anti-oxidizing agent. $CHCl_3$, $H_2O$, 30%, 60% MeOH, MeOH fractions were examined antioxidative activity by DPPH, test of inhibition on NO production. It was revealed that 30%, 60% MeOH and $CHCl_3$ fractions had significant antioxidative activity. In 30% MeOH and 60% MeOH, $CHCl_3$ fraction, six compounds were isolated and elucidated as adenosine(I), guanosine(II), peucedanol 7-O-$\beta$-D-apiofuranosyl(1$\rightarrow$6)-$\beta$-glucopyranoside(III), peucedanol 7-O-$\beta$-D-glucopyranoside(IV), peucedanol(V) and scopoletin(VI) by physicochemical data and spectroscopic methods. (Negative FAB-MS, $^{1}H-NMR$, $^{13}C-NMR$). The results from antioxidative activity screening for the each compound showed that compound IV was relatively superior antioxidant ability. In anti-inflammatory activation assay, compound III, IV, VI had concentration-dependent-activity and compound IV had superior anti-inflammatory ability. These results suggest that Peucedani Radix might be developed as a potent anti-oxidative, anti-inflammatory agents and ingredients for related functional foods.

• Journal of Environmental Health Sciences
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• v.36 no.3
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• pp.236-246
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• 2010

In preparative anti-corrosive coating experiments, polyaniline was obtained by reacting an oxidizing agent with the monomer aniline. Further, the primer coating was prepared using a variety of widely-used materials such as urethane resin. For the top coating, epoxy resin and acrylic urethane resin were used. Characteristics of the coatings were assessed according to KS and ASTM specifications, and the structure of the polyaniline was characterized using FT-IR and TGA. For analysis of anti-corrosive properties in salt-spray experiments, measurements of the oxidation state of iron and surface atomic analysis were conducted using XPS and SEM-EDX. Unlike general anti-corrosive coatings which exhibit anti-corrosive effects only as a primer coating, the anti-corrosive coatings using polyaniline as the anti-corrosive pigment showed a marked synergistic effect with the top coatings. In other words, the top coatings not only produce a fine view effect, but also increase, through interaction with the primer coatings, the resistance to diffusion of corrosive factors from the external environment. It was also found that, unlike the heavy metal oxide-forming layer of the passive barrier alone, the polyaniline anti-corrosive pigment oxidized iron at the interface with the iron substrate to form a passive barrier in the oxidic layer, and itself formed a potential barrier layer with anti-corrosive factors from the external environment. Although the passive layer was damaged, the damaged area did not become completely oxidized iron; on the contrary, it showed a tendency to reduction. This can be interpreted such that a passive layer is formed again on the damaged area, and that at the same time there is a tendency to self-healing.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.433-439
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• 2017

This research investigates the manufacturing process and characteristics analysis of $BKNO_3$ (Boron Potassium Nitrate) as pyrotechnic are commonly found in the aerospace, defense, and automotive industries. A solid pyrotechnic mixture is composed of an oxidizing agent, fuel, and binder. Precipitation process was used to uniformly mix the raw material. Through the analysis of the material characteristics and thermal response is designed optimum ratio by NASA CEA program. It was compared by performing the evaluation of these size/shape/sensitivity/calorimetry characteristics.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.1
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• pp.58-63
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• 2020

THPP is a type of metallic complex explosive used in initiators, consisting of TiH₂ and KClO₄. In this case KClO₄ includes ClO₄^- which is a harmful substance that may cause thyroid dysfunction or tumors. In this study KIO₄ is applied to a new type of environmentally friendly explosive as a substitute to the conventional KClO₄. Tests were carried out to see if KIO₄ can be made a successful replacement for KClO₄.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.73-81
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• 2000

The removal of ferrous iron (Fe(II)) in groundwater is generally achieved by simple aeration or the addition of oxidizing agent. Aeration followed by solid-liquid separation is the most commonly used as physico-chemical treatment method for iron removal. In general aeration has been shown to be very efficient in insolubilizing ferrous iron at the pH level greater than 6.5. In this study pH was maintained over 6.5 using limestone granules under constant aeration to oxidize ferrous iron. In batch experiments, oxidation rate of ferrous iron was investigated under different conditions including limestone granule size. initial concentration of the ferrous iron, pH, temperature and ionic strength in groundwater. The pH in groundwater was presumed as the most important factor determining oxidation rate of ferrous iron. According as the size of the limestone granules decreased, the pH of the iron contaminated water increased quickly and oxidation of the ferrous iron was achieved immediately too. The oxidation rate of the ferrous iron was found to be proportion to initial concentration of the iron contaminated water, temperature and ionic strength, respectively.

• Resources Recycling
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• v.26 no.1
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• pp.30-36
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• 2017

Leaching experiments of anode slime were performed with several inorganic acids (HCl, $HNO_3$ and $H_2SO_4$) together with thiourea and thiosulfate solution to recover gold and silver. Gold was not dissolved at all into these inorganic acids in the absence of any oxidizing agents. At the same concentration of inorganic acid, the leaching of percentage of Ag was the highest in the sulfuric acid solution. The leaching percentage of silver increased with the increase of HCl concentration owing to the formation of $AgCl_2{^-}$. Copper, nickel and zinc except tin was almost dissolved in these inorganic acids but no tin was dissolved in nitric acid solution. Most of Au and Ag were dissolved into the mixture of sulfuric acid and thiourea solution. Thiosulfate could dissolve some silver from the anode slime but no gold was dissolved by this agent.