• 대한화학회지
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• 제45권1호
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• pp.25-30
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• 2001

Nile blue와 sodium periodate의 산화반응에서 촉매로 작용하는 rhodium(Ⅲ) 이온의 농도변화에 따른 형광세기를 측정하여 rhodium(Ⅲ) 이온을 정량하는 방법에 대하여 연구하였다. 반응계의 pH, nile blue, sodium periodate, trioctylphosphine oxide(TOPO)의 농??및 온도가 반응속도에 주는 영향을 조사하였다. 최적 실험조건에서 rhodium(Ⅲ) 이온의 직선범위는 100ng/mL~0.1ng/mL 이었고 검출한계는 0.01ng/mL이었다. 또한 본 방법으로 Rh(Ⅲ)이온을 정량할 때의 일부 방해이온 효과에 대해서도 조사하였다.

• Carbon letters
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• 제6권1호
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• pp.1-5
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• 2005

Isotropic pitch based carbon fibers were exposed to isothermal oxidation in carbon dioxide gas to study the activation kinetics under the temperature of 800~$1100^{\circ}C$. The kinetic equation $f=1-{\exp}(-at^b)$ was introduced and the constant b was obtained in the range of 0.92~1.25. It was shown that the activated carbon fiber shows the highly specific surface area (SSA) when the constant b comes close to 1. The activation kinetics were evaluated by the reaction-controlling regime (RCR) according to changes of the apparent activation energy with changes of the conversion. It was observed that the activation energies increase from 47.6 to 51.2 kcal/mole with the conversion increasing from 0.2 to 0.8. It was found that the pores of the activated carbon fiber under the chemical reaction were developed well through the fiber.

• 한국자동차공학회논문집
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• 제10권6호
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• pp.80-89
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• 2002

The flame structure and soot formation in Acetylene-Air nonpremixed jet flame are numerically analyzed. We employed two variable approach to investigate the soot formation and oxidation processes. The present soot reaction mechanism involves nucleation, surface growth, particle coagulation, and oxidation steps. The gas phase chemistry and the soot nucleation, surface growth reactions are coupled by assuming that the nucleation and soot mass growth has the certain relationship with the concentration of pyrene and acetylene. We also employed laminar flamelet model to calculate the thermo-chemical properties and the proper soot source terms from the information of detailed chemical kinetic model. The numerical and physical model used in this study successfully predict the essential features of the combustion processes and soot formation characteristics in the reaction flow field.

• Environmental Analysis Health and Toxicology
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• 제12권3_4호
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• pp.1-13
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• 1997

First- and second-order kinetic oxidation rates of trichlorobenzenes (TCBs) were obtained and compared by a chemical activation system (CAS) which mimics mixed functional oxidase activity. The system consists of EDTA, ferrous sulfate, ascorbic acid, and $H_2O_2$ in potassium phosphdte buffer (monobasic at pH 7.4). The rate of transformation in CAS was enhanced in the presence and absence of catalase in the sequence 1, 2, 3-TCB < 1, 2, 4-TCB < 1, 3, 5-TCB. In general, the rates of degradation were greater in the test media with catalase. The effect of photolysis on the degradation of the TCBs with the CAS were examined. Sensitized photolysis with nitrite, Fenton's reagent, TiO$_2$ and triethylamine (TEA) studied in concert with the CAS demonstrated significant enhancement of the degradation rate of TCBs. Disappearance rates of TCBs in CAS with prior photolysis or prior photosensitization were at least 10-fold higher than the sum of the rate for each single experiment. This study proves that the combination of the CAS and photolysis can be used as a suitable technique for enhancing degradation of TCBs in aqueous systems.

• 대한기계학회논문집B
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• 제33권1호
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• pp.46-52
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• 2009

The oxidation of surrogate mixtures for gasoline fuel was studied numerically in perfectly stirred reactor(PSR) to develope the needed detailed reaction mechanism. The reaction mechanism was assembled with the mechanisms for the oxidation of iso-octane or kerosene. It was shown that the reaction model predicted reasonably well the concentration profiles of fuel and major species reported in the literature. As the addition of kerosene into iso-octane as fuel was increased, the concentrations of $C_2H_2$ and benzene became high. Especially benzene known as a carcinogen appeared at a very high concentration in the flue gases.

• Bulletin of the Korean Chemical Society
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• 제22권8호
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• pp.909-913
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• 2001

The kinetics of oxidative decarboxylation of pyruvic acid and benzoylformic acid by peroxomonophosphoric acid (PMPA) in aqueous medium have been investigated. The reaction follows second order-first order each in PMPA and substrate concentration a t constant pH. The reactivity of different peroxo species in the oxidation has been determined. Activation energy and thermodynamic parameters have been computed. A plausible mechanism consistent with the observed results is proposed.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2000년도 제21회 KOSCO SYMPOSIUM 논문집
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• pp.33-46
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• 2000

In the present study, a systematic chemical kinetic calculations were made to investigate the augmentation of NO-$NO_2$ conversion due to the addition of various hydrocarbons (methane, ethylene, ethane, propene, propane) in the nonthermal plasma treatment. It is included in the present conclusion that the reaction between hydrocarbon and oxygen radicals induced by electron collision, is believed to be a primarily process for triggering the overall NO oxidation and the eventual NOx reduction. Upon the completion of the initiating step, various radicals (OH, $NO_2$ etc.) successively produced by hydrocarbon decomposition form the primary path of NO-$NO_2$ conversion. When the initiating step is not activated, hydrocarbon consumption rate appeared to be very low, thereby the targeted level of NO conversion can only be achieved by the addition of more input energy. Present study showed ethylene and propene to have higher affinity with 0 radical under all conditions, thereby both of these hydrocarbons show very fast and efficient NO-$NO_2$ oxidation. It was also shown that propene is superior to ethylene in the aspect of NOx removal.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2000년도 제20회 KOSCO SYMPOSIUM 논문집
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• pp.178-188
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• 2000

In the present study, a systematic chemical kinetic calculations were made to investigate the augmentation of $NO-NO_{2}$ conversion due to the addition of various hydrocarbons (methane, ethylene, ethane, propene, propane) in the nonthermal plasma treatment. It is included in the present conclusion that the reaction between hydrocarbon and oxygen radicals induced by electron collision, is believed to be a primarily process for triggering the overall NO oxidation and the eventual NOx reduction. Upon the completion of the initiating step, various radicals (OH, $HO_{2}$ etc.) successively produced by hydrocarbon decomposition form the primary path of $NO-NO_{2}$ conversion. When the initiating step is not activated, hydrocarbon consumption rate appeared to be very low, thereby the targeted level of NO conversion can only be achieved by the addition of more input energy. Present study showed ethylene and propene to have higher affinity with 0 radical under all conditions, thereby both of these hydrocarbons show very fast and efficient $NO-NO_{2}$ oxidation. It was also shown that propene is superior to ethylene in the aspect of NOx removal.

• Environmental Engineering Research
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• 제20권2호
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• pp.181-189
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• 2015

A composite material was tested to eliminate phenol in aqueous solution combining adsorption on activated carbon and photocatalysis with $TiO_2$ in two different ways. A first implementation involved a sequential process with a loop reactor. The aim was to reuse this material as adsorbent several times with in situ photocatalytic regeneration. This process alternated a step of adsorption in the dark and a step of photocatalytic oxidation under UV irradiation with or without $H_2O_2$. Without $H_2O_2$, the composite material was poorly regenerated due to the accumulation of phenol and intermediates in the solution and on $TiO_2$ particles. In presence of $H_2O_2$, the regeneration of the composite material was clearly enhanced. After five consecutive adsorption runs, the amount of eliminated phenol was twice the maximum adsorption capacity. The phenol degradation could be described by a pseudo first-order kinetic model where constants were much higher with $H_2O_2$ (about tenfold) due to additional ${\bullet}OH$ radicals. The second implementation was in a continuous process as with a fixed bed reactor where adsorption and photocatalysis occurred simultaneously. The results were promising as a steady state was reached indicating stabilized behavior for both adsorption and photocatalysis.

• 상하수도학회지
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• 제27권1호
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• pp.39-47
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• 2013

This study demonstrates the oxidative degradation of pharmaceutical compounds during ozonation of surface waters in Ulsan. Diclofenac, carbamazepine, bezafibrate, and ibuprofen were selected as surrogate pharmaceutical compounds, and ozonation experiments were performed using raw waters collected from the Sayeon Dam and the Hoeya Dam in Ulsan. Diclofenac and carbamazepine which have high reactivity with molecular ozone showed higher removal efficiencies than bezafibrate and ibuprofen during ozonation. The addition of tert-butanol, a hydroxyl radical scavenger, increased the removal efficiencies of diclofenac and carbamazepine by increasing the ozone exposure. However, the oxidation of bezafibrate and ibuprofen was inhibited by the presence of tert-butanol due to the suppression of the exposure to hydroxyl radical. The elimination of the selected pharmaceuticals could be successfully predicted by the kinetic model base on the $R_{ct}$ concept. Depending on the experimental condition, $R_{ct}$ values were determined to be $(1.54{\sim}3.32){\times}10^{-7}$ and $(1.19{\sim}3.04){\times}10^{-7}$ for the Sayeon Dam and the Hoeya Dam waters, respectively. Relatively high $R_{ct}$ values indicate that the conversion of $O_3$ into $^{\cdot}OH$ is more pronounced for surface waters in Ulsan compared to other water sources.