• Journal of the Korean Chemical Society
• /
• v.32 no.6
• /
• pp.567-574
• /
• 1988

Kinetic studies on the vanadium(IV)-catalyzed oxidation of dimethylsulfoxide by hydrogen peroxide in water and aqueous methanol and ethanol show that the reaction is the first order in the concentration of dimethylsulfoxide and hydrogen peroxide, respectively. Activation parameters are also measured for the oxidation of dimethylsulfoxide. It is suggested that the rate determining step is a process involving oxidation of dimethylsulfoxide as the result of nucleophilic attack by the sulfur on the O-O bond of vanadium(V)-peroxide complex.

• Journal of Environmental Science International
• /
• v.17 no.12
• /
• pp.1307-1314
• /
• 2008

Hydrogen gas is used as a fuel for the proton exchange membrane fuel cell (PEMFC). Trace amount of carbon monoxide present in the reformate $H_2$ gas can poison the anode of the PEMFC. Therefore, preferential oxidation (PROX) of CO is essential for reducing the concentration of CO from a hydrogen-rich reformate gas. In this study, conventional Pt/$Al_2O_3$ catalyst was prepared for the preferential oxidation of CO. The effects of catalyst preparation method, additive, and hydrogen on the performances of PROX reaction of CO were investigated. Water treatment and addition of Ce enhanced catalytic activity of the Pt/$Al_2O_3$ catalyst at low temperature below $100^{\circ}C$.

• Nuclear Engineering and Technology
• /
• v.54 no.8
• /
• pp.3130-3139
• /
• 2022

Direct containment heating (DCH) is one of the potential factors leading to early containment failure. DCH is closely related to safety analysis and containment performance evaluation of nuclear power plants. In this study, a DCH prediction program was developed to analyze the DCH loads of containment vessel. The phenomenological model of debris dispersal, metal oxidation reaction, debris-atmospheric heat transfer and hydrogen jet burn was established. Code assessment was performed by comparing with several separate effect tests and integral effect tests. The comparison between the predicted results and experimental data shows that the program can predict the key parameters such as peak pressure, temperature, and hydrogen production in containment well, and for most comparisons the relative errors can be maintained within 20%. Among them, the prediction uncertainty of hydrogen production is slightly larger. The analysis shows that the main sources of the error are the difference of time scale and the oxidation of cavity debris.

• Journal of Environmental Health Sciences
• /
• v.26 no.4
• /
• pp.49-57
• /
• 2000

This study was carried out to find the optimal condition to treat refractory organic matter which can’t treat clearly with biological treatment and to find the optimal division dosage and division dose timing in the modification of Fenton oxidation which is used resolve the problem that hydrogen peroxide is too expensive. The results are following; 1. The highest TOC removal efficiency was 41% and color removal efficiency was 64% when the dilution magnitude of leachate is fold. This suggests that dilution is efficiency when high concentration of leachate is treated. 2. The removal efficiency of TOC and color increased up to the molar ratio between ferrate and hydrogen peroxide was 1:1. However above that ratio, removal efficiency hardly increased. The highest removal efficiency of TOC and color were 38% and 71% when the mole ratio of ferrate to hydrogen peroxide was 1.5:1. 3. When the mole ratio between ferrate and hydrogen peroxide was fixed, the removal efficiency of TOC and color increased as the dosage of hydrogen peroxide increased. 4. pH of samples were adjusted at pH 3, 5, 7, 9, 11. After oxidation reaction, pH of samples were dropped to 2.59, 2.54, 5.34, 6.36 and 9.68. The highest color removal efficiency was 75.7% when initial pH was at pH 7. 5. The removal of TOC and color was ended within 10. min. and the removal efficiency increased logarithmically within 10min. However after 10 min., the removal efficiency of hardly increased. 6. The color removal efficiency was higher with modification of fentone oxidation than that with fentone oxidation by 5%. Optimal division dosage ratio was 1:1 and optimal dose timing ratio was 2:1. However the TOC removal efficiency was not higher with modification of Fenton oxidation than that with Fenton oxidation.7. The CO $D_{Mn}$ /BO $D_{5}$ Ratio decreased with the time went by. It meant bioresolution increased as time went by. However, after 15 min., the CO $D_{Mn}$ /BO $D_{5}$ Ratio did not decrease any more. 8. In the case of $H_2O$$_2$ Divisiom Dose experiment, the increase of bioresolution was highest at the $H_2O$$_2$ Division dosage Ratio of 3:7.3:7.

• Journal of Environmental Science International
• /
• v.5 no.1
• /
• pp.51-59
• /
• 1996

The purpose of this study was to evaluate the partial oxidation of the biological treatment plant effluents using Fenton's reagent as a pretreatment step prior to a tertiary biological oxidation of these effluents. Fenton's reagent was evaluated as a pretreatment process for inhibitory or refractory organics. Based on the Fenton oxidation system, the petrochemical wastewater treatment plant effluent was shown to have significant improvement in toxicity after oxidation with hydrogen peroxide. For example, at ranee of 42 ∼ 184 mg/L COD of petrochemical plant effluents, the COD removal efficiencies were from 38.2% to 60.1% after reaction with hydrogen peroxide 200 mg/L and Fe2+ 100 mg/L and reaction time was 30 minutes. The total TOC reduction were about 15.8∼22.4% with same test condition and difference between the overall removal rate and BOD/COD ratio after Fenton's oxidation estabilished in the biodegradation and otherwise meets the discharge standard or reuse for cooling tower make-up water.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.2
• /
• pp.629-630
• /
• 2014

• Transactions of the Korean hydrogen and new energy society
• /
• v.10 no.2
• /
• pp.101-106
• /
• 1999

Hydrogen solubility in internally oxidized Pd-Mo(Al) alloys has been studied at 323 K from the measurements of pressure-composition(p-c) isotherms. Internal oxidation of $Pd_{0.985}Al_{0.015}$ and $Pd_{0.97}Mo_{0.03}$ alloys results in the precipitation of Al and Mo particles in a matrix of pure Pd. It has been observed that the presence of the aluminum and molybdenum oxide precipitates results in an enhanced hydrogen solubility in the dilute phase region of Pd-H in a Pd/aluminum(molybdenum)oxide composites. Hydrogen solubility enhancements due to the presence of residual stresses around ceramic particles have been observed from p-c isotherms determined at 323 K after oxidation at 1073 K. The solubility enhancements in completely internally oxidized alloys are greater than that in partially oxidized alloys. The stress fields near the ceramic precipitates are the major source of the solubility enhancements. Transmission electron microscopy indicates that alumina precipitates are nanometer-sized and coherent with the Pd matrix after oxidation.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.29 no.4
• /
• pp.47-54
• /
• 2021

In this study, the performance of a honeycomb-type hydrogen oxidation catalyst to remove hydrogen in a hydrogen economy society to secure leaking hydrogen. The Pd/TiO₂ catalyst was prepared based on a liquid phase reduction method that is not exposed to a heat source, and it was showed through H₂-chemisorption analysis that it existed as very small active particles of 2~4 nm. In addition, it was found that the metal dispersion decreased and the active particle size increased as the reduction reaction temperature increased. It was meant that the active metal particle size and the hydrogen oxidation performance were in a proportional correlation, so that it was consistent with the hydrogen oxidation performance reduction result. The prepared catalyst was coated on a support in the form of a honeycomb so that it could be applied to the hydrogen industrial process. When 20 wt% or more of the AS-40 binder was coated, oxidation performance of 90% or more was observed under low-concentration hydrogen conditions. It was showed through SEM analysis that long-term catalytic activity can be expected by enhancing the adhesion strength of the catalyst and preventing catalyst desorption. It is a basic research that can secure safety in a hydrogen society such as gasification, organic resource, and it can be utilized as a system that can respond to unexpected safety accidents in the future.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.288-288
• /
• 2012

The oxidation characteristics of tungsten line pattern during the carbon-based mask layer removal process using oxygen plasmas and the reduction characteristics of the WOx layer formed on the tungsten line surface using hydrogen plasmas have been investigated for sub-50 nm patterning processes. The surface oxidation of tungsten line during the mask layer removal process could be minimized by using a low temperature ($300^{\circ}K$) plasma processing instead of a high temperature plasma processing for the removal of the carbon-based material. Using this technique, the thickness of WOx on the tungsten line could be decreased to 25% of WOx formed by the high temperature processing. The WOx layer could be also completely removed at the low temperature of $300^{\circ}K$ using a hydrogen plasma by supplying bias power to the tungsten substrate to provide an activation energy for the reduction. When this oxidation and reduction technique was applied to actual 40 nm-CD device processing, the complete removal of WOx formed on the sidewall of tungsten line could be observed.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.3
• /
• pp.445-453
• /
• 2007

The effect of an electrochemically generated oxidation-reduction potential and electric pulse on ethanol production and growth of Saccharomyces cerevisiae ATCC 26603 was experimented and compared with effects of electron mediators (neutral red, benzyl viologen, and thionine), chemical oxidants (hydrogen peroxide and hypochlorite), chemical reductants (sulfite and nitrite), oxygen, and hydrogen. The oxidation (anodic) and reduction (cathodic) potential and electric pulse activated ethanol production and growth, and changed the total soluble protein pattern of the test strain. Neutral red electrochemically reduced activated ethanol production and growth of the test strain, but benzyl viologen and thionine did not. Nitrite inhibited ethanol production but did not influence growth of the test strain. Hydrogen peroxide, hypochlorite, and sulfite did not influence ethanol production and growth of the test strain. Hydrogen and oxygen also did not influence the growth and ethanol production. It shows that the test strain may perceive electrochemically generated oxidation-reduction potential and electric pulse as an environmental factor.