• Title, Summary, Keyword: Oxidation and Reduction Products

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Determination of Chemical Compositions and Oxidation States for Corrosion Products in LiCl Molten Salts

  • Park, Yong-Joon;Pyo, Hyung-Ryul;Kim, Do-Yang;Jee, Kwang-Yong;Kim, Won-Ho
    • Nuclear Engineering and Technology
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    • v.32 no.5
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    • pp.514-520
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    • 2000
  • The mechanism of corrosion behavior has to be understood clearly to select an optimum material for handling molten salts to be used in the oxide reduction process of PWR spent fuel. In this study, the oxidation states of corrosion products on the surface of Inconel 600 and 800H as well as their chemical compositions and structural informations were determined by using XPS, ICP-AES, AAS, EPMA and XRD after the corrosion experiment with lithium molten salts at 75$0^{\circ}C$ for 25 hours. Nickel and oxygen were detected from the corrosion products on the surface of Inconel plates and chromium was found to be dissolved out into lithium molten salts leaving cracks on the surface. The corrosion products were identified as metal oxides such as Fe$_2$O$_3$, Cr$_2$O$_3$, NiO, NiFe$_2$O$_4$and MnO by using XPS and XRD.

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Synthesis of Cyclitol Derivatives (IV) Electrolytic Reduction of DL-epi-inosose-2 (Cyclitol 유도체 합성에 관한 연구 (제4보) DL-epi-inosose-2의 전해환원)

  • Sohn, Joo-Hwan;Nam, Chong-Woo;Park, Heung-Cho
    • Journal of the Korean Chemical Society
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    • v.16 no.2
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    • pp.93-99
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    • 1972
  • To obtain the various kinds of inositol stereomers, we have selected the process of electrolytic reduction of DL-epi-inosose-2 using Ni, Ta, Cu, Mo, Pb, Sn, W, Cd and Hg etc., as cathode. We think that this process gives greater variety than chemical processes. DL-epi-inosose-2 was synthesized by chemical oxidation of myo-inositol, dissolved in aqueous solution of potassium hydroxide, and used as electrolytic solution. To prevent anodic oxidation of cathode products the H-type diaphragm cell was used. As the results of paper chromatography of cathodic products, we obtained the $R_f$ values of myo-inositol and epi-inositol were in good agreement with literature values.

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Degradation of energetic compounds using an integrated zero-valent iron-Fenton process

  • Oh Seok-Young;Kim Byung J.;Chiu Pei C.;Cha Daniel K.
    • 한국지구물리탐사학회:학술대회논문집
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    • pp.493-500
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    • 2003
  • The effect of reductive treatment with elemental iron on the extent of mineralization by Fenton oxidation was studied for the explosive 2,4,6-trinitrotoluene (TNT) and hexahydro-l,3,5-trinitro-l,3,5-triazine (RDX) using a completely-stirred tank reactor (CSTR). The results support the hypothesis that TNT and RDX are reduced with elemental iron to products that are oxidized more rapidly and completely by Fenton's reagent. Iron pretreatment enhanced the extent of TOC removal by approximately $20\%\;and\;60\%$ for TNT and RDX, respectively. Complete TOC removal was achieved for TNT and RDX solutions with iron pretreatment under optimal conditions. On the other hand, without iron pretreatment, complete mineralization of TNT and RDX solutions were not achieved even with much higher $H_2O_2$ and $Fe^{2+}$ concentrations. The bench-scale iron treatment-Fenton oxidation integrated system showed more than $95\%$ TOC removal for TNT and RDX solutions under optimal conditions. The proposed zero-valent iron-Fenton process was evaluated with pink water from the Iowa Army ammunition plant. Results from batch and column experiments show that TNT, RDX, and octahydro-l,3,5,7-tetranitro-l,3,5,7-tetrazocine (HMX) were completely removed from the pink water and that triaminotoluene (TAT) and ${NH_4}^+$ were recovered as products in reduction with zero-valent iron. By using an integrated system, $83.3\pm4.2\%$ of TOC was removed in a CSTR with 10 mM of $Fe^{2+}$ and 50 mM of $H_2O_2$. These results suggest that the reduction products of TNT and RDX are more rapidly and completely mineralized by Fenton oxidation and that a sequential iron treatment-Fenton oxidation process may be a viable technology for pink water treatment.

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Beneficial Effects of Traditional Seasonings on Quality Characteristics of Fermented Sausages

  • Seong, Pil-Nam;Seo, Hyun-Woo;Kang, Sun-Moon;Kim, Yoon-Seok;Cho, Soo-Hyun;Kim, Jin-Hyoung;Hoa, Van-Ba
    • Asian-Australasian Journal of Animal Sciences
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    • v.29 no.8
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    • pp.1173-1180
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    • 2016
  • Though traditional seasonings are widely used in many dishes, however, no attention has been paid to the investigation of their effects on quality characteristics of food products. The present investigation was undertaken to study the effects of incorporating several traditional seasonings including doenjang (fermented soybean paste), gochu-jang (red pepper paste), fresh medium-hot, and hot peppers, and fresh garlic on the lipid oxidation, cholesterol content and sensory characteristics of fermented sausages. Six fermented sausage treatments (5 with 1% (w/w) each test seasoning and 1 without added test seasoning (control) were prepared. The addition of seasonings generally had beneficial effects on the improvement of fermented sausage's quality however the effects differed depending on the each type of seasonings added. Significant lower pH values were found in all fermented sausages made with the seasonings while, lower levels of lipid oxidation were found in the treatments with hot peppers and garlic as compared with the control (p<0.05). The treatment with seasonings did not cause color or texture defects in the products whereas the sausages made with gochu-jang had significantly higher Commission International de $l^{\prime}Eclairagea^{\ast}$ (redness) value in comparison with the control. Noticeably, incorporating doenjang, medium-hot peppers, hot peppers and garlic resulted in reduction of 26.50, 32.54, 47.04, and 48.54 mg cholesterol/100 g samples, respectively (p<0.05). Higher scores for the sensory traits such as aroma, taste, color and acceptability were also given for the sausages made with seasonings. The current work demonstrates that the test seasonings represent potentially natural ingredients to be used for producing healthier fermented sausages.

Chemical-nutritional parameters and volatile profile of eggs and cakes made with eggs from ISA Warren laying hens fed with a dietary supplementation of extruded linseed

  • Ianni, Andrea;Palazzo, Fiorentina;Grotta, Lisa;Innosa, Denise;Martino, Camillo;Bennato, Francesca;Martino, Giuseppe
    • Asian-Australasian Journal of Animal Sciences
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    • v.33 no.7
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    • pp.1191-1201
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    • 2020
  • Objective: The aim of this study was to evaluate the chemical-nutritional parameters, oxidative stability and volatile profile of eggs and cakes made with eggs from laying hens fed with a dietary supplementation of extruded linseed. Methods: Two thousand ISA Warren laying hens were randomly divided into two groups: a control group was fed with a standard diet while the experimental group received the same diet supplemented with 7% of extruded linseed. The trial lasted 84 days, in which three samplings of laid eggs were performed. Samples of eggs and food systems arising from eggs were then analyzed in order to obtain information about β-carotene and total flavonoid content, antioxidant activity, fatty acid profile, lipid oxidation, and volatile profile. Results: Linseed induced the increase of α-linolenic acid with consequent reduction of the ω-6/ω-3 ratio (4.3:1 in egg yolk); in addition to this, was evidenced the cholesterol reduction and the significant increase in total flavonoids and β-carotene, although no variations were detected in antioxidant capacity. Even in cooked products there was not only a direct effect of linseed in increasing α-linolenic acid, but also in inducing the reduction of cholesterol and its major oxidation product, 7-ketocholesterol. The dietary linseed integration was also shown to affect the volatile profile of baked products. Conclusion: Data confirmed that dietary supplementation with extruded linseed resulted in food products with interesting implications for human health. With regard to the volatile profile of baked products it would be necessary undertake further sensorial analysis in order to evaluate any variations on flavor and consumer acceptability.

Characteristics of Solid Fuel Oxidation in a Molten Carbonate Fuel Cell

  • Lee, Choong-Gon;Kim, Yu-Jeong;Kim, Tae-Kyun;Lee, Sang-Woo
    • Journal of Electrochemical Science and Technology
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    • v.7 no.2
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    • pp.91-96
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    • 2016
  • Oxidation behaviours of ash free coal (AFC), carbon, and H2 fuels were investigated with a coin type molten carbonate fuel cell. Because AFC has no electrical conductivity, its oxidation occurs via gasification to H2 and CO. An interesting behaviour of mass transfer resistance reduction at higher current density was observed. Since the anode reaction has the positive reaction order of H2, CO2 and H2O, the lack of CO2 and H2O from AFC results in a significant mass transfer resistance. However, the anode products of CO2 and H2O at higher current densities raise their partial pressure and mitigate the resistance. The addition of CO2 to AFC reduced the resistance sufficiently, thus the resistance reduction at higher current densities did not appear. Electrochemical impedance results also indicate that the addition of CO2 reduces mass transfer resistance. Carbon and H2 fuels without CO2 and H2O also show similar behaviour to AFC: mass transfer resistance is diminished by raising current density and adding CO2.

Development of Control Technology for Acid Mine Drainage by Coating on the Surface of Pyrite using Chemicals (산성광산배수의 발생저감을 위한 황철석 표면의 피막형성 기술개발)

  • Ji, Min-Kyu;Yoon, Hyun-Sik;Ji, Eung-Do;Lee, Woo-Ram;Park, Young-Tae;Yang, Jung-Seok;Jeon, Byong-Hun;Shim, Yon-Sik;Kang, Man-Hee;Choi, Jae-Young
    • Journal of Soil and Groundwater Environment
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    • v.15 no.4
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    • pp.46-52
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    • 2010
  • Acid mine drainage occurs when sulfide minerals are exposed to an oxidizing environment. The objective of this study was to inhibit the oxidation of pyrite by applying various coating agent such as $KH_2PO_4$, MgO and $KMnO_4$ over its surface as an oxidation inhibitors. Experiments were conducted for 8 days to test the feasibility of oxidation inhibitors. The optimal condition of coating agent for standard pyrite and IK mine was the combination of 0.01M $KH_2PO_4$, 0.01M NaOAc and 0.01M NaClO. Otherwise, for YD mine the combination of 0.01M $KMnO_4$, 0.01M NaOAc and 0.01M NaClO. The $SO_4^{2-}$ reduction efficiency of pyrite, IK and YD mine samples was 70, 92 and 84%, respectively. For 8 days, no significant increase of $SO_4^{2-}$ from pyrite sample coated with inhibitor was observed. The pH of solution remains in between 4 to 6 for the reaction conditions.

Electrochemical nitrate reduction using a cell divided by ion-exchange membrane

  • Lee, Jongkeun;Cha, Ho Young;Min, Kyung Jin;Cho, Jinwoo;Park, Ki Young
    • Membrane Water Treatment
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    • v.9 no.3
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    • pp.189-194
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    • 2018
  • Electrochemical reduction of nitrate was studied using Zn, Cu and (Ir+Ru)-Ti cathodes and Pt/Ti anode in a cell divided by an ion exchange membrane. During electrolysis, effects of the different cathode types on operating parameters (i.e., voltage, temperature and pH), nitrate removal efficiency and by-products (i.e., nitrite and ammonia) formation were investigated. Ammonia oxidation rate in the presence of NaCl was also determined using the different ratios of hypochlorous acid to ammonia. The operating parameter values were similar for all types of cathode materials and were maintained relatively constant. Nitrate was well reduced and converted mostly to ammonia using Zn and Cu cathodes. Ammonia, produced as a by-product of nitrate reduction, was oxidized in the presence of NaCl in the electrochemical process and the oxidation performance was enhanced upon increasing the hypochlorous acid-to-ammonia ratio to 1.09:1. Zn and Cu cathodes promoted the nitrate reduction to ammonia and the produced ammonia was finally removed from solution by reacting with hypochlorite ions. Using Zn or Cu cathodes, instead of noble metal cathodes, in the electrochemical process can be an alternative technology for nitrate-containing wastewater treatment.

Improvement of Oxidative Stability of Myoglobin and Lipid with Vitamin E in Meat (식육내 비타민 E에 의한 육색소와 지질의 산화 안정성 향상)

  • Faustman, Cameron;Lynch, Michael P.;Jeong, Jin-Yeun;Joo, Seon-Tea
    • Food Science of Animal Resources
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    • v.23 no.1
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    • pp.86-95
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    • 2003
  • Potential mechanisms by which vitamin E improves oxidative stability of myoglobin are documented. The basis by which this lipid-soluble antioxidant, ${\alpha}$-tocopherol, protects water-soluble oxymyoglobin is beginning to be understood. Recent evidence suggests that ${\alpha}$-tocopherol delays the release of prooxidative products of lipid oxidation from biomembranes, which in turn delays oxymyoglobin oxidation and the concomitant loss of desirable beef color. ${\alpha}$, ${\beta}$-Unsaturated aldehydes are one class of lipid oxidation products that enhance oxymyoglobin oxidation in vitro and appear to act by covalently binding to the protein. If ${\alpha}$-tocopherol delays the formation of these reactive aldehydes, then this could inhibit the prooxidative effect of these oxidation products toward oxymyoglobin. Additionally, ${\alpha}$-tocopherol may exert part of its color-stabilizing effect in beef by enhancing the metmyoglobin reduction.

Methanol Partial Oxidation over Commercial CuO-ZnO-Al2O3 Catalysts (CuO-ZnO-Al2O3 상업용 촉매에서의 메탄올 부분산화반응)

  • Lim, Mee-Sook;Suh, Soong-Hyuck;Ha, Ki-Ryong;Ahn, Won-Sool
    • Transactions of the Korean hydrogen and new energy society
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    • v.13 no.2
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    • pp.119-126
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    • 2002
  • The methanol partial oxidation using commercial $CuO/ZnO/Al_2O_3$ catalysts in a plug flow reactor was studied in the temperature range of $200{\sim}250^{\circ}C$ at atmospheric pressure, It was achieved the high activities by Cu-based catalysts and the selectivity of $CO_2$/$H_2$ was 100% when $O_2$ was fully convened. The reactivity changes and their hysteresis with increasing/decreasing temperatures were observed due to the chemical state differences between the oxidation and the reduction on the Cu surface, It was suggested as the two-step reaction: the complete oxidation and the following steam reforming for methanol, which was indicated by the distributions of final products vs. the residence time. In addition, the complete oxidation step was shown to be extremely fast and the total reaction rate can be controlled by the steam reforming reaction.