• Journal of Korean Society of Environmental Engineers
• /
• v.37 no.10
• /
• pp.558-562
• /
• 2015

This study was tested to evaluate the effect of the six different combinations of microbubble, catalyst, and air as oxidant on the sludge and organic matter reduction. When all of microbubbles and catalyst, and an oxidizing agent (under Conditions 1) such as air were used, the sludge was removed more than 99%, and TCOD and SCOD removal was 58% and 13%, respectively. This result was the highest value of six conditions. In the following order, the sludge reduction of the microbubbles with air (Condition 2) and catalyst with air (condition 4) was 95% and 93.1%, respectively. TCOD removal was found to be each 53% and 47%. When the microbubbles were used with oxidant like air, the removal of sludge and organic matter was high. All of these values were higher than that of using only microbubbles and catalyst without air. In the microbubbles and catalyst react under air supply condition, OH-radicals were generated in the reaction process. These OH-radicals in the reaction process decomposed the pollutants by the strong oxidizing power. In all conditions with air, the sludge reduction was high removal rate more than 93% and TCOD removal was over 47%.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.2
• /
• pp.297-302
• /
• 2011

Acid drainage generated by pyrite oxidation has caused the acidification of soil and surface water, the heavy metal contamination and the corrosion of structures in abandoned mine and construction sites. The applicability of Na-acetate (Na-OAc) buffer and/or Na-silicate solution was tested for suppressing pyrite oxidation by reacting pyrite containing rock and treating solution and by analyzing solution chemistry after the reaction. A finely ground Mesozoic andesite containing 10.99% of pyrite and four types of reacting solutions were used in the applicability test: 1) $H_2O_2$, 2) $H_2O_2$ and Na-silicate, 3) $H_2O_2$ and 0.01M Na-OAc buffer at pH 6.0, and 4) $H_2O_2$, Na-silicate and 0.01M Na-OAc buffer at pH 6.0. The pH in the solution after the reaction with the andesite sample and the solutions was decreased with increasing the initial $H_2O_2$ concentration but the concentrations of Fe and $SO_4^{2-}$ were increased 10 - 20 times. However, the pH of the solution after the reaction increased and the concentrations of Fe and $SO_4^{2-}$ decreased in the presence of Na-acetate buffer and with increasing Na-silicate concentration at the same $H_2O_2$ concentration. The solution chemistry indicates that Na-OAc buffer and Na-silicate suppress the oxidation of pyrite due to the formation of Fe-hydroxide and Fe-silicate complex and their coating on the pyrite surface. The effect of Na-OAc buffer and Na-silicate on reduction of pyrite oxidation was also confirmed with the surface examination of pyrite using scanning electron microscopy (SEM). The result of this study implies that the treatment of pyrite containing material with the Na-OAc buffer and Na-silicate solution reduces the generation of acid drainage.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 2001.11a
• /
• pp.94-94
• /
• 2001

Prostaglandin endoperoxide H synthase (PGHS) catalyzes the committed step in prostaglandins and thromboxane A$_2$-- oxygenation of arachidonic acid to the hydroperoxy endoperoxide PGG$_2$, followed by reduction PGG$_2$to the alcohol PGH$_2$. The two reactions by PGHS -- cyclooxygenase and peroxidase -- occur at distinct but structurally and functionally interconnected sites. The peroxidase reaction occurs at a heme-containing active site located near the protein surface. The cyclooxygenase reaction occurs in a hydrophobic channel in the core of the enzyme. Initially a peroxide reacts with the heme group, yielding Compound I and an alcohol derived from the oxidizing peroxide. Compound I next undergoes an intramolecular reduction by a single electron traveling from Tyr385 along the peptide chain to the proximal heme ligand, His388, and finally to the heme group. Following the binding of arachidonic acid, Tyr385 tyrosyl radical initiates the cyclooxygenase reaction by abstracting the 13-pro(5) hydrogen atom to give an arachidonyl radical, which sequentially reacts with two molecules of oxygen to yield PGG$_2$. In order to characterize PGHS peroxidase active site, we examined various lipid peroxides with purified recombinant ovine PGHS proteins and determined the rate constants. The results have shown that twenty-carbon unsaturated fatty acid hydroperoxides have similar efficiency in peroxidation by PGHS, irrespective of either the location of hydroperoxy group or the number of double bonds. It was also confirmed by the subsequent study with PGHS peroxidase active site mutants.

• Transactions of the Korean hydrogen and new energy society
• /
• v.26 no.4
• /
• pp.347-356
• /
• 2015

A study has been conducted numerically to investigate the lifted flat syngas flame structure of impinging jet flame configuration with the global strain rates in 10% hydrogen content. In this study, the effects of strain rate were major parameters on chemistry kinetics and flame structure at stagnation point. The numerical results were calculated by SPIN application of the CHEMKIN package. The strain rates were adjusted with Reynolds numbers of premixed syngas-air mixture. Different flame shapes were observed with different strain rates. As strain rate has increased, the flame temperature and axial velocity have been decreased due to the flame heat loss increment, and the OH radical reaction zones become narrower but each mole fractions are still constant. Also, the reversion of $H_2O$ product near stagnation point has been found out when strain rate has increased. This phenomenon is attributed to the rapid production of oxidizing radical reaction such as the R12 ($H+O_2(+M)=HO_2(+M)$), which makes the R18 ($HO_2+OH=O_2+H_2O$) reaction increment.

• Applied Chemistry for Engineering
• /
• v.3 no.4
• /
• pp.710-716
• /
• 1992

Ethylphenyl carbarmate(EPC) was synthesized by oxidative CO carbonylation of aniline in the presence of transition metal catalysts and alkali metal halide cocatalysts at $120^{\circ}C$ under the pressure of 79atm. Oxygen gas was used for oxidizing agent. Kinetics of the reaction was studied and activation energies with different catalysts were estimated. About 100% conversion to EPC and 95% selectivity was obtained in 5 hour reaction. 5% Pd/C was more effective than 5% Rh/C. Effectiveness of cocatalysts was in the order of KI>KBr>KCl. As the temperature increased from $75^{\circ}C$ to $120^{\circ}C$, the conversion rate increased. The reaction was apparent first order and the activation energies with 5% Pd/C and 5% Rh/C were 5.647 and 5.780 kcal/mol, respectively.

• 한국연소학회:학술대회논문집
• /
• 2006.10a
• /
• pp.260-265
• /
• 2006

An experimental study on the catalytic reformer adopted in the auxiliary power unit system of solid oxide fuel cell was conducted. A 3-fluid nozzle, by which liquid fuel such as diesel, water and air are sprayed and uniformed mixed, was designed and used in this study. An electrically heated monolith inserted in the reformer was used for the vaporization of fuel and water in the transient state of reformer. The reformer uses the partial oxidizing reaction at the catalyst and the supply of water prevents the flame combustion in the spraying zone and lessens the deactivation of catalyst. The result showed that the reforming of liquid fuel can be started by the electrically heated monolith and the 3-fluid nozzle can give the uniform mixing of fuel, water and air. It was also found that the reformer fueled by n-hexadecane can make the reformate, at best, containing $H_2$ at 15.5% and CO at 11.5% that are used as fuel in the solid oxide fuel cell.

• Korean Journal of Materials Research
• /
• v.3 no.1
• /
• pp.7-11
• /
• 1993

Abstract Oxidation kinetics of silicon oxide films formed by rapid thermal oxidizing Si substrate in $N_2$O ambient studied. The data on $N_2$0 oxidation shows that the interfacial nitrogen-rich layers results in oxide growth in the parabolic regime by impeding oxidant diffusion to the Si$O_2$-Si interface even for ultrathin oxides. The activation energy of parablic rate constant, B, is about 1.5 eV, and the energy increses with oxide thickness.

• Journal of Environmental Health Sciences
• /
• v.21 no.2
• /
• pp.12-19
• /
• 1995

The objectives of this research prograln were to study the ozonation characteristics of phenol contaminated wastewater in the continuous packed column reactor (PCR) and the bubble column reactor (BCR) using ozone that has a strong oxidizing potential, and to provide the fundamentals of ozonizing the phenol contaminated wastewater. Among various influencing factors on phenol decomposition through the oxidation by ozone, phenol/ozone mde ratio was chosen as reaction parameters. Concerning the phenol/ozone mde ratio, as the influent phenol concentration increased from 30 mg/l to 150 mg/l, the phenol removal efficiency decreased from 99% for 30 mg/l to 83.7% for 150 mg/l, in PCR. PCR also showed higher treatment efficiency than BCR by 1% for 30 mg/l and 2.2% for 150 mg/l, respectively. The ozone utilization efficiency of PCR for the phenol concentration 30 mg/l was higher than that of BCR while the efficiency of both reactors was 99.9% for the phenol concentration of 150 mg/l.

• Textile Coloration and Finishing
• /
• v.28 no.4
• /
• pp.253-270
• /
• 2016

In the wool textile industry, the necessity for technology development has been steadily raised to create improved fineness and yarn count of existing wool yarns with thick fineness for ensuring higher quality grades of wool yarn. Recently, through controlling fineness of wool yarn for making finer wool in relation with environmentally-friendly and high-sensitivity trend, a differentiated continuous drawing process where the quality of wool can be artificially manipulated has been suggested in the latest textile industry. This study investigated the basic conditions during the continuous drawing process which enable to manufacture wool yarn with fine count by controlling reducing agent treatment, physical drawing and drying after reducing agent treatment, and oxidizing agent post-treatment conditions. Furthermore, this study reviewed the drawing effects by applying the basic conditions for reduction and oxidation reaction in the drawing processes of wool/cashmere, wool/silk, wool/polyester blended yarns as well as such wool yarns. Also, in order to review the practicability, this study examined the physical properties and dyeability of drawn wool yarn applied textile materials in comparison with normal wool yarn applied textile materials.

• Nuclear Engineering and Technology
• /
• v.12 no.2
• /
• pp.81-87
• /
• 1980

Insulin was labelled with $^{125}$ I using lactoperoxidase as an oxidizing agent. The reaction product was purified via two stages: a starch gel electrophoresis(SGE) and a Sephadex gel filtration (SF). Upon comparison of the labelling yields and the bindabilities of the labelled insulin to its antibody, it has been found that the enzyme method shows higher yields (50%) and the better bindability to its antibody than the conventional chloramine-T method (35%). By checking the insulin blank labelling mixture with a SGE, a paper chromatography, and a radioautography technique, a by-product in the lactoperoxidase method has been identified. The separated fractions in SGE and SF were also analyzed and discussed.