• Journal of Korean Society of Environmental Engineers
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• v.33 no.10
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• pp.731-738
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• 2011

In this study AOPs of $O_3/UV$ radiation, $O_3/Mg(OH)_2/UV$ radiation and $O_3/MgO/UV$ radiation system for phenol treatment in aqueous solution was performed in a laboratory scale circulating batch reacter. Flow rate of ozone 1.0 L/min, ozone concentrations $150{\pm}10mg/L$ was maintained constantly at the above-mentioned oxidation processes. During the oxidation processes the $COD_{Cr}$ and TOC was measured in the composition. The pseudo first-order rate constants of the processes was $5.12{\times}10^{-5}$, $1.19{\times}10^{-4}$ and $1.79{\times}10^{-4}sec^{-1}$, and the activation energy was 3.03, 1.79 and $2.32kcal{\cdot}mol^{-1}$ at $20^{\circ}C$, respectively. It was found that both $Mg(OH)_2$ and MgO had remarkable accelerations on degradation of phenol and removal of COD in water. On this basis, $O_3/MgO/UV$ system is an effective and feasible routes for catalytic ozonation of phenol in water.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.89-90
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• 2008

본 연구에서는 PECVD(Plasma Enhanced CVD) 에서 사용하는 유해 가스인 $SiH_4$ 대신에 유기 사일렌 반응 물질인 TEOS(Tetraethyl Orthosilicate, Si$(OC_2H_5)_4)$를 이용하여 상압 화학 기상 증착법 (Atmospheric Pressure CVD, APCVD)으로 실리콘 산화막을 증착하고 박막의 조성과 특성 및 화학적, 전기적 특성들을 살펴보았다. TEOS 반응원료를 이용한 CVD 공정에서 공정 온도를 낮추기 위한 방법으로 강력한 산화제인 오존을 이용하여 공정온도를 $400^{\circ}C$이하로 낮췄으며, 유리기판 상의 ELA(Excimer Laser Annealing)처리된 다결정 실리콘 기판에 트랜지스터 소자를 제작하고, 게이트 절연막으로의 전기적 특성을 살펴보았다.

• Journal of Korean Society on Water Environment
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• v.28 no.5
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• pp.704-716
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• 2012

This paper provides a detailed account of pilot testing conducted at South Lake Tahoe (California), the Ddukdo (Seoul) water treatment plant (WTP) and the Bokjung (Seongnam) WTP between February, 2010, and February, 2012. The objectives were first, to characterize the reactions of ozone with hydrogen peroxide (Peroxone) for Han River water following sand filtration, second to determine empirical ozone and hydrogen peroxide doses to remove a taste-and-odor surrogate 2-methylisoborneol (MIB) using an advanced oxidation process (AOP) configuration and third, to determine the optimum dosing configuration to reduce residual ozone to a safe level at the exit of the process. The testing was performed in a real-time plant environment at both low- and high seasonal water temperatures. Experimental results including ozone decomposition rates were dependent on temperature and pH, consistent with data reported by other researchers. MIB in post-sand-filtration water was spiked to 40-50 ng/L, and in all cases, it was reduced to below the specified target level (7 ng/liter) and typically non-detect (ND). It was demonstrated that Peroxone could achieve both MIB removal and low effluent ozone residual at ozone+hydrogen peroxide doses less than those for ozone alone. An empirical predictive model, suitable for use by design engineers and operating personnel and for incorporation in plant control systems was developed. Due to a significant reduction in the ozone reaction/decomposition at low winter temperatures, results demonstrate the hydrogen peroxide can be "pre-conditioned" in order to increase initial reaction rates and achieve lower ozone residuals. Results also indicate the method, location and composition of hydrogen peroxide injection is critical to successful implementation of Peroxone without using excessive chemicals or degrading performance.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.1
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• pp.85-92
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• 2010

In this study, odorous compounds emitted from various wastewater treatment were treated with using the non-thermal plasma reaction, and the effluent gas from the plasma reactor was introduced to a waste sludge reactor to achieve simultaneous sludge reduction. Hydrogen sulfide, the model odorous compound, was removed at 70% using the plasma reaction, and greater than 99% removal efficiency was observed when treated by the sludge reactor. In addition, the sludge reactor showed a high efficiency of ozone removal. As ozone reacted with sludge, oxidation with organic matters took place, and total COD decreased by 50~60% and soluble COD increased gradually. As a result, the integrated process consisting of the non-thermal plasma and the sludge reactor can be successfully applied for the simultaneous treatment of malodorous gas and waste sludge.

• Journal of the Korean Society of Urban Environment
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• v.18 no.4
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• pp.391-399
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• 2018

In this study, Diazinon which is the most widely used organophosphorus pesticides (OPPs) among pesticides was removed by ozone/hydrogen peroxide advanced oxidation process (Peroxone AOP). Diazinon is mainly found in groundwater, drinking water, rivers and ponds that are near agricultural areas using the pesticide. Accumulation of Diazinon on the body in the form of metabolites causes neurotoxicity, confusion, dizziness and vomiting. Diazinon is not easily removed by conventional water treatment processes. This study investigated the Diazinon removal characteristics with OH radicals with strong oxidizing power generated by using ozone and hydrogen peroxide. We determined optimal hydrogen peroxide/ozone injection molar ratio and confirmed the elimination reaction to initial Diazinon concentration, pH and DOC concentration, which are factors influencing the removal efficiency. Domestic researches on pesticide removal in the environment are much less than the cases of overseas. This study is expected to provide a basis for the process design for pesticide removal.

• Applied Chemistry for Engineering
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• v.22 no.3
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• pp.261-265
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• 2011

The sterilization effects of atmospheric pressure plasma with the mixture of argon and oxygen were analyzed. The plasma reactor with the shape of dielectric barrier discharge produced the uniform distribution of glow discharge and generated ozone gas effectively according to the various process parameters. The sterilization for E. coli was affected by power, oxygen ratio in the mixture gas, treatment time and distance between reactor and sample. The concentration of ozone was a major source for the sterilization of E. coli, which was enhanced by the increase of power and oxygen ratio. In this study, the effect of atmospheric pressure plasma treatment for the sterilization was confirmed and its result can deliver the atmospheric pressure plasma treatment as the novel sterilization method instead of conventional methods.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.5
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• pp.382-391
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• 2009

Atmospheric speciated mercury concentrations including total gaseous mercury (TGM) and reactive gaseous mercury (RGM) were measured in Chuncheon from March 2006 to November 2008. Average concentrations were 2.10 ${\pm}$ 1.50 ng/$m^3$ and 3.00 ${\pm}$ 3.14 pg/$m^3$ for TGM and RGM, respectively. RGM concentrations were higher during daytime than nighttime probably because of high photochemical activities. We found that RGM concentration considerably increased as ozone increased when fog occurred, indicating that ozone was the important oxidant for $Hg^0$ in aqueous phase. TGM concentration showed positive correlations with CO and $PM_{10}$ which can transport in long-range, but there was no correlation with $NO_2$. Considering that major source of mercury is combustion process, this result showed that local sources did not significantly impact on TGM concentration in Chuncheon. Five-day backward trajectories were calculated for the samples representing high and low concentrations of TGM, and determined that industrialized area of China including Shenyang and Beijing influenced TGM concentrations in Chuncheon.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.50 no.2
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• pp.143-151
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• 2024

Ozone is a colorless, toxic gas that is produced when nitrogen oxides and hydrocarbons undergo a photochemical oxidation reaction in the sun's rays. Even at low concentrations, it affects the respiratory system, causing coughing and other harmful effects. It was confirmed that ozone was generated from nitrogen plasma among cosmetic raw materials, and it was found that the concentration of ozone decreased after 1 day. On the other hand, ozone was not detected in ozone-free plasma generated with argon gas. Therefore, we aimed to produce ozone-free cosmetics by utilizing ozone-free plasma. For efficient plasma processing, the non-sinking method was utilized to inject the plasma into layer separation mists, toners, and ampoules, and the stability was observed. It was found that the successful injection of plasma in the layer separation mist was higher than the other two formulations, but decreased sharply compared to the toner and ampoule. It was found that the ozone-free plasma used did not affect the stability of the layer separation mist, toner, and ampoule under low temperature (4 ℃), room temperature (25 ℃), and high temperature (37 ℃, 50 ℃) conditions. Therefore, this study suggests the importance of ozone-free plasma for cosmetic potential and stability of each formulation.

• Applied Chemistry for Engineering
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• v.23 no.3
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• pp.302-307
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• 2012

Advanced oxidation processes (AOP) such as O3/activated carbon process and O3/catalysts process were used to compare the decomposition of phenol. Catalysts such as Pd/activated carbon (Pd/AC), Mn/activated carbon (Mn/AC), Co/activated carbon (Co/AC) and Fe/activated carbon (Fe/AC) were prepared by impregnation of Pd, Mn, Co and Fe into the activated carbon of pellet form, respectively. Based on an hour of reactions, the following descending order for the decomposition ratios of dissolved O3 to the 1.48 mg/L of saturated dissolved O3 was observed: Mn/AC (45%) > Pd/AC (42%) > Co/AC (33%) > AC (31%) > Fe/AC (27%). The removal efficiencies of phenol were also arranged in the descending order of AOP as follows: Mn/AC (89%) > Pd/AC (85%) > Co/AC (77%) > AC (76%) > Fe/AC (71%). The remaining ratios (C/Co) of TOC (total organic carbon) after an hour of experiments were arranged in the ascending order of AOP as follows : Pd/AC (0.29) < Mn/AC (0.36) < AC (0.40) < Co/AC (0.49) < Fe/AC (0.51). However, the catalytic effects in the Co/AC and the Fe/AC processes were little in comparison with O3/AC process. The maximum concentrations of intermediates such as hydroquinone and catechol formed from the decomposition of phenol were arranged in the ascending order of AOP as follows: Pd/AC < Fe/AC < Co/AC < AC < Mn/AC. In the case of Pd/AC process, these intermediates were almost disappeared after an one hour of reaction.

• Applied Chemistry for Engineering
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• v.32 no.6
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• pp.659-663
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• 2021

10 m³/min (CMM) multi-pollutants abatement system was successfully developed by effectively integrating ozone oxidation, wet scrubbing, and wet electrostatic precipitation for the simultaneous removal of particulate matters (PMs) and NOx in a semiconductor fabrication process. The sophisticated control and optimization of operating parameters were conducted to maximize the destruction and removal efficiency of NOx. In particular, the stability test of a wet electrostatic precipitator was carried out in parallel for 30 days to validate the reliability of core parts including a power supply. An O₃/NO ratio, which is the most important operating parameter, was optimized to be about 1.5 and the optimization of wet scrubbing with a reducing agent made it possible to analyze the contribution of neutralization reaction.