• Bulletin of the Korean Chemical Society
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• 제34권11호
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• pp.3227-3232
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• 2013

A novel Cu-Co-O composite nanocatalyst was designed and prepared for the ozonation of phenol. A synergistic effect of copper and cobalt was observed over the Cu-Co-O composite nanocatalyst, which showed higher activity than either copper or cobalt oxide alone. In addition, the Cu-Co-O composite revealed good activity in a wide initial pH range (4.11-8.05) of water. The fine dispersion of cobalt on the surface of copper oxide boosted the interaction between catalyst and ozone, and the surface Lewis acid sites on the Cu-Co-O composite were determined as the active sites. The Raman spectroscopy also proved that the Cu-Co-O composite was quite sensitive to the ozone. The trivalent cobalt in the Cu-Co-O composite was proposed as the valid state.

• 한국산학기술학회논문지
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• 제18권4호
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• pp.544-549
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• 2017

본 논문은 오존 방식 선박평형수 처리의 핵심 장치인 이젝터에 대하여 회전 운동하는 구동 유체가 기체-액체 이젝터의 효율에 미치는 영향에 관한 연구이다. 이젝터는 오존을 구동 노즐을 통해 분사되는 고압 액체(선박평형수)와 주변부의 저압 기체 간의 운동량 교환으로 발생되는 부압에 의해 기체(오존)를 흡입시키는 장치이다. 기존의 이젝터는 단순한 형태로 구동 유체가 분사되지만, 본 논문에서는 구동 노즐부에 회전 유도장치를 적용하여 구동 유체가 회전 운동하며 분사될 수 있도록 한다. 구동 유체의 회전 운동 유무에 따른 유동 특성을 파악하기 위하여 전산유체해석을 이용하였으며, 구동 유체의 압력과 유량, 흡입부에 발생하는 흡입 유체의 부압과 흡입 유량, 그리고 토출 압력이 예측되었다. 그 결과를 바탕으로 회전유도 장치가 적용된 이젝터의 효율은 22.25%로 산출되었으며, 구동 유체의 회전 운동이 없는 이젝터에 비해 약 1.7%의 효율이 향상되었다. 마지막으로 전산유체해석의 타당성을 검증하고자 실험 장치를 구축하여 회전 유도 장치가 적용된 이젝터에 대한 실험을 수행하였으며, 전산유체해석 결과와 비슷한 결과를 얻을 수 있었다.

• 설비공학논문집
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• 제19권5호
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• pp.403-410
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• 2007

In this study, natural refrigerants and their mixtures that can supplement and replace R12 and R134a in automobile air-conditioners are studied. R134a is currently used as the refrigerant in new motor vehicle air conditioners, replacing the ozone depleting refrigerant R12. Although R134a has no ozone depletion potential, it has a relatively large global warming potential, approximately 1300 times that of $CO_2$ over a 100 year time horizon. For this reason, performance of natural refrigerants and their mixtures containing R152a, RE170 (Dimethylether, DME) and R600a (Isobutane) are measured under 2 different temperature conditions. They were tested in a refrigerating bench tester with an open type compressor. The test bench provided about 4 kW capacity and water and water/glycol mixture were employed as the secondary heat transfer fluids. Test results show that the coefficient of performance (COP) of these refrigerants is up to 21.55% higher than that of R12 in all temperature conditions. Overall, these fluids provide good performance with reasonable energy savings without any environmental problem and thus can be used as long term alternatives for automobile air-conditioners.

• 한국물환경학회지
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• 제16권4호
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• pp.445-457
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• 2000

This study was carried out comparing with ozone oxidation and photocatalytic degradation for removal of geosmin. In the change of pH, Ozonation, UV-Germicidal lamp and Halogen lamp irradiation and Halogen $lamp/TiO_2$ Powder was very slowly changing, but UV-Germicidal $lamp/TiO_2$ Powder was rapidly changed from 7.0 to 7.7 until 300min of irradiation time, and varied a little after. Geosmin degradation ratio was as following, UV-Germicidal $lamp/TiO_2$ $Powder(200mg/L){\geq}O_3$ > UV-Germicidal $lamp/TiO_2$ $Pw(100mg/L)$ > UV-Germicidal lamp > Halogen lamp. The result of investigation of generated by-products were 3-Heptanone, two sort of aldehydes and three sort of alcohols by ozonation. But It was not generated by photocatalytic degradation.

• 한국물환경학회지
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• 제16권4호
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• pp.479-490
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• 2000

This study investigated the removal characteristics, Microcystin decomposition and generation of by-products when aqueous Microcystis sp. is oxidized by ozone. The concentration of Microcystin (MC) in aqueous solution has been found by HPLC analysis to decrease continuously by ozonation after the initial, abrupt increase. The kinetic constant of the decomposition of MC-RR and -LR were 0.0596 and 0.0243, respectively. This means that removal efficiency of MC-RR by its oxidative decomposition is preferable compared with that of MC-LR. On the other hand, it has been found that the decomposition product, TOC, exhibits the continuous decrease in the concentration by further ozonation, while DOC and UV-254 increase temporarily until 10 minutes before the decrease. Furthermore, the GC/MSD analysis has revealed that the ozonation of Microcystis sp. for 100minutes affords five kinds of aldehydes, six kinds of alcohols, and trans-1, 2-dimethyl-cyclopropane.

• 대한환경공학회지
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• 제33권2호
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• pp.113-119
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• 2011

오존을 이용한 잉여슬러지 감량화 시스템이 결합된 생물학적 처리 공정에서 잉여슬러지의 무배출에 따른 생물반응조내의 영향 및 처리수질을 검토하였다. 잉여슬러지 인발량 배수($SDN_{min}$)가 3인 조건에서 잉여슬러지의 pH를 4 이하로 전 처리한 후 오존주입율 0.03 g $O_3/g$ SS로 처리한 결과 잉여슬러지의 인발 없이 안정적인 생물학적 처리가 가능하였다. $OUR_{max}$ 실험 결과, 오존주입율 0.03 g $O_3/g$ SS의 조건에서 대부분의 슬러지는 미생물 활성이 없어지는 것으로 조사되었다. 잉여슬러지의 가용화에 따른 생물반응조내에서의 MLVSS/MLSS의 변화는 거의 없었고, 반응조내 미생물의 인 축적 현상도 관측되지 않았다. 잉여슬러지 가용화 후 생물학적 처리수의 유기물 및 SS의 농도 증가 현상은 관측되지 않았고, 생물반응조내의 질산화 및 탈질율 증가로 유출수중의 T-N 농도가 감소하는 효과를 나타내었다. T-P의 경우에는 잉여슬러지의 무배출로 인해 대부분이 제거되지 않고 유출수중에 함유되어 유출되는 것으로 조사되었다.

• 한국어병학회지
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• 제12권1호
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• pp.32-41
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• 1999

오존처리 해수중에 함유하는 잔류 옥시던트(TRO)가 양식 넙치의 생존, 혈액성상과 삼투질 농도, 산소소비 및 아가미 조직에 미치는 독성 영향을 조사하였다. TRO에 노출된 넙치의 48-hr 및 96-hr $LC_{50}$은 각각 26.4 와 22.3ppb이었고, 47ppb에서는 3시간 이내에 모두 치사하였으나 13ppb에서는 96시간 동안 폐사발생이 없었다. TRO 24~39ppb 농도범위에 노출된 넙치의 hematocrit, 헤모글로빈, 적혈구 수, 혈중 sodium과 chloride 이온 및 삼투압 농도는 TRO 농도가 높을수록 유의하게 증가하였고, 아가미 조직은 아가미 상피층이 모세혈관으로부터 박리되고, 괴사와 상피새포의 증생이 관찰되었다. 산소소비율은 TRO 농도가 높고, 노출이 계속될수록 감소하였다. 13ppb에서는 아가미 조직과 생리상태에 미치는 변화는 관찰되지 않았으나 혈당은 유의하게 증가하였다. 그러나 활성탄으로 TRO를 제거한 대조구에서는 오존의 독성 영향은 관찰되지 않았다. 잔류오존에 노출된 넙치는 삼투질 농도의 생리적 불균형 및 아가미 손상과 상피세포의 증생에 의한 산소섭취 부족이 치사를 유발하는 것으로 나타났다. 본 연구의 결과 해산어 양식장에서 오존을 사용할 경우에는 오존처리수중의 TRO는 제거하여야 하며, 비록 저농도라도 장기간 노출되면 양식어류의 생존과 생리상태에 미치는 영향은 현저할 것으로 평가되었다.

• 한국물환경학회지
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• 제37권3호
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• pp.168-174
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• 2021

Mixing is a very important unit in water treatment process. A mechanical stirring method is generally used for mixing, but recently, the use of pressurized water mixing method (pump diffusion flash mixer) has gained interest because it is more advantageous in terms of mixing time, noise, energy consumption, and maintenance. The following conclusions were obtained from the study of pressurized water mixing method by Computational Fluid Dynamics. Firstly, the mixing degree in the pipe increased as the density of water increased. Secondly, even if the relative velocity between flow rate in the pipe and the pressurized water was constant, the mixing degree decreased as the flow velocity in the pipe increased. Thirdly, the stronger the injection energy the higher the mixing degree. It was also found that the mixing degree was greatly affected by the injection velocity as compared to the injection flow amount. Finally, the required energy to achieve 95% mixing degree at the distance of 10 times diameter in big pipes of 500 mm to 3000 mm was 0.3 to 4.5 kJ. The result of this study could be used in the process design of injection with water purification chemicals, such as, ozone, chlorine, and coagulant.

• 한국대기환경학회지
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• 제34권3호
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• pp.457-468
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• 2018

To improve understanding of the physico-chemical characteristics of aerosols in the national park and comparing the air pollution between national park and the urban area nearby national park, the aerosol characterization study was conducted in Bukhansan National Park, Seoul, from July through September 2017. Semi-continuous measurements of $PM_{2.5}$ using PILS (Particle Into Liquid System) coupled with IC (Ion Chromatography) and TOC (Total Organic Carbon) analyzer allowed quantification of concentrations of major ionic species($Cl^-$, $SO_4{^{2-}}$, $NO_3{^-}$, $Na^+$, $NH_4{^+}$, $K^+$, $Mg{^{2+}}$ and $Ca{^{2+}}$) and water soluble organic carbon (WSOC) with 30-minute time resolution. The total mass concentration of $PM_{2.5}$ was measured by T640 (Teledyne) with 5-minute time resolution. The black carbon (BC) and ozone were measured with a minute time resolution. The timeline of aerosol chemical compositions reveals a strong influence from urban area (Seoul) at the site in Bukhansan National Park. Inorganic aerosol composition was observed to be dominated by ammoniated sulfate at most times with ranging from $0.1{\sim}32.6{\mu}g/m^3$ (6.5~76.1% of total mass of $PM_{2.5}$). The concentration of ammonium nitrate, a potential indicator of the presence of local source, ranged from below detection limits to $20{\mu}g/m^3$ and was observed to be highest during times of maximum local urban (Seoul) impact. The total mass of $PM_{2.5}$ in Bukhansan National Park was observed to be 10~23% lower than the total mass of $PM_{2.5}$ in urban area (Gireum-dong and Bulgwang-dong, Seoul). In general, ozone concentration in Bukhansan National Park was observed to be similar or higher than urban sites in Seoul, suggesting additional biogenic VOCs with $NO_x$ from vehicle emission were to be precursors for ozone formation in Bukhansan National Park.

• 혜화의학회지
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• 제20권1호
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• pp.161-174
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• 2011

Objectives : This paper researched methods of washing Herb medicine through research papers of washing Crops Materials and Methods : We collected research papers on Washing crops. Then we analysed them according to washing methods. Results : The following results were obtained in this study. 1. Herbal fruit, wash using a conveyor belt. 2. Leafy herbs, soak in a chlorine solution or ozone solution and rinse it. sometimes using micro bubble system. 3. Radix, wash with high pressure sprinkling water. 4. Cortex, wash under running water by hand washing. Conclusion : Herb medicines need a washing methods for each region. so Herbs should be washed in a suitable methods for each region.