• 청정기술
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• 제27권1호
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• pp.9-16
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• 2021

Active Matrix Organic Light-Emitting Diode (AMOLED) 봉지 공정은 수분과 산소에 매우 취약하기 때문에, 수분과 산소의 함량이 최소화된 고순도의 질소를 사용하여야 한다. 본 연구의 목적은 AMOLED 봉지 공정에 사용하는 질소에서 산소를 제거하기 위한 용도로 사용되는 구리계 촉매를 최적화하는 것이다. CuO, Al2O3, 또는 ZnO의 조성으로 이루어진 2성분계 및 3성분계 촉매를 공침법을 통해서 제조하였다. 제조된 촉매들을 BET, XRD, TPR, XRF의 분석장비를 활용하여 촉매의 특성을 분석하였다. 촉매의 산소 제거 성능을 확인하기 위해 고정층 반응기에서 촉매 산소 제거 반응 실험을 수행하고 산소 분석기를 통해 산소 함량을 측정하였다. 또한 사용된 촉매의 반복 재생을 통해 촉매의 재사용 성능을 검증하였다. CuO와 Al2O3 비율이 6 : 4, 7 : 3 및 8:2로 제조된 2 성분계 촉매의 특성과 산소 제거 능력을 비교하였다. CuO와 Al2O3의 비율이 8:2인 촉매의 환원성이 가장 높았는데, 이는 CuO의 분산도가 가장 높기 때문이다. 결과적으로, 2성분계 촉매 중에서 CuO와 Al2O3의 비율이 8 : 2 인 촉매의 산소 제거 능력이 가장 우수한 것으로 나타났다. CuO : Al2O3 의 비율이 8:2인 촉매에 ZnO를 2 wt% 넣어준 촉매가 3성분계 촉매 중에는 가장 우수한 산소제거 능력을 보였으며, 이는 뛰어난 환원성에 기인한다고 할 수 있다. 또한 이 촉매는 재생 실험을 통해서도 산소 제거능력이 유지된다는 것을 확인하였다.

• 한국환경과학회지
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• 제6권2호
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• pp.141-152
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• 1997

The pilot plant had been made so as to be an association system from the various items managed to have degrees of efficiency and It have been done to consider the experimental result with irradiance period and pH influence of all major things to treatment function of Waste Stabilization Pond. The results are as following. The attained results for continuous & cyclic irradiance 1. 24L.-reactor was prior to 12L.-12D.-reactor on oxygen generation & algal production ability. 2. 24L.-reactor was prior to 12L.-12D.-reactor on nutrients removal efficiency. 3. In 24L.-reactor it maintained 5mg/L∼6mg/L, DO concent enough to a fish's survival. The attained results for pH condition 1. Oxygen generation ^ algal production in pH 4-reactor were higher than those in pH 10-reactor. 2. The acidic condition at pH 4 and alkalic condition at pH 10 did not so much affect an algal growth and nutrients removal. The attained results for whole 1. In view of the results appeared as [(NH3-N)+(NO3-N)] removal efficiency, 89.1%∼93.9% and PO4-P removal efficiency, 34.3%∼83.7% & COD removal efficiency, 88.5%∼93.9%. It is possible to treat the wastewater with starch and pH which have been known as thedifficult problem. 2. At the point of non using methanol to nitrificate NO3-N, the nutrients removal method by using an algal growth is the most economical method in the whole nutrients removal methods. 3. The nutrients removal method by using an algal growth contributes to natural ecosystem. 4. The nutrients removal method by using an algal growth is excellant in the prevention against the eutrophication.

• Membrane and Water Treatment
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• 제6권4호
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• pp.339-349
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• 2015

Experiments were carried out using granular activated carbon (GAC) adsorption techniques to treat wastewater contaminated with organic compounds caused by diverse human activities. Two techniques were assessed: adsorbent GAC prepared from coconut shell (GACC) and adsorbent GAC from palm shell (GACP). A comparison of these two techniques was undertaken to identify ways to improve the efficiency of the treatment process. Analysis of the processed wastewater showed that with GACC the removal efficiency of biochemical oxygen demand (BOD), chemical oxygen demand (COD), turbidity, total suspended solids (TSS) and total dissolved solids (TDS) was 65, 60, 82, 82 and 8.7%, respectively, while in the case of GACP, the removal efficiency was 55, 60, 81, 91 and 22%, respectively. It can therefore be concluded that GACC is more effective than GACP for BOD removal, while GACP is better than GACC for TSS and TDS removal. It was also found that for COD and turbidity almost the same results were achieved by the two techniques. In addition, it was observed that both GACC and GACP reduced pH value to 7.9 after 24 hrs. Moreover, the optimal time period for removal of BOD and TDS was 1 hr and 3 hrs, respectively, for both techniques.

• 상하수도학회지
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• 제35권2호
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• pp.135-142
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• 2021

The activity of anaerobic ammonium oxidation (ANAMMOX) immobilized in synthetic media (Poly Ethylene Glycol, PEG) and granular form was evaluated comparatively to investigate the effect of influent nitrogen concentration and exposure of oxygen. In ANAMMOX granule reactor, when concentration of influent total nitrogen increased to 500mg/L, removal efficiency of ammonium, nitrite and nitrate were shown to 90.5±6.5, 96.6±4.9, and 93.2±6.1%, respectively. In the case of the PEG gel, it showed lower nitrogen removal performance, resulting in that the removal efficiency of ammonium, nitrite and nitrate were shown to 83.3±13.0, 96.4±6.1, and 90.3±7.5%, respectively. In second step, when exposed to oxygen, the nitrogen removal performance in the ANAMMOX granule reactor also remained stable, but the activity of PEG gel ANAMMOX was found to be inhibited. Consequently, the PEG gel ANAMMOX was a higher sensitivity than that of granular ANAMMOX with two variables applied in this study.

• 한국대기환경학회지
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• 제18권3호
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• pp.173-182
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• 2002

We investigated the effects of operating variables, such as electrical. reactor and gas parameters on toluene removal and discharge property in the dielectric barrier discharge (DBD) process. The toluene removal was initiated with the energy transfer to the reactor by loading of voltages higher than the discharge onset value. The energy transfer and toluene removal increased with the applied voltage. Higher removal rate was observed with smooth surface electrode despite of lower energy transfer compared with the coarse electrode, because more uniform discharge can be obtained on smooth surface state. The decrease of dielectric material thickness enhanced the removal efficiency by increasing the discharge potential. The toluene removal efficiency decreased with the increase of the inlet concentration. The increase of gas retention time enhanced the removal efficiency by the increase of energy density. The oxygen and humidity contents seem to exert significant influences on the toluene removal by dominating the generation of electrons, ions, and radicals which are key factors in the removal mechanism.

• 한국수산과학회지
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• 제37권6호
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• pp.498-504
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• 2004

Removal of waste generated by Paralichthys olivaceus in the seawater aquarium using a foam separator was investigated. Protein concentration without a foam separator continuously increased until 3 days after stocking and reached at 25 mg/L after 5 days stocking, but protein concentration became lower than the initial protein concentration (2.5 mg/L) with a foam separator. The trends of other fish wastes such as ammonia, total suspended solids (TSS) and chemical oxygen demand (COD) were similar to protein. Dissolved oxygen (DO) in the aquarium decreased below 6.0 mg/L without a foam separator, but with a foam separator the average DO in the aquarium was 7.3 mg/L. Foam separation with the increase of superficial air velocity (SAV) was more effective than that with the fixed SAV. This study showed that wastewater. treatment of seawater aquarium using a foam separator is effective method for a fish waste removal and oxygen supply.

• 한국환경과학회지
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• 제28권7호
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• pp.629-637
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• 2019

The purpose of this study was to evaluate the effect of high-salinity wastewater on the microbial activity of Aerobic Granule Sludge (AGS). Laboratory-scale experiments were performed using a sequencing batch reactor, and the Chemical Oxygen Demand (COD), nitrogen removal efficiency, sludge precipitability, and microbial activity were evaluated under various salinity injection. The COD removal efficiency was found to decrease gradually to 3.0% salinity injection, and it tended to recover slightly from 4.0%. The specific nitrification rate was 0.043 - 0.139 mg $NH_4{^+}-N/mg$ $MLVSS{\cdot}day$. The specific denitrification rate was 0.069 - 0.108 mg $NO_3{^-}-N/mg$ $MLVSS{\cdot}day$. The sludge volume index ($SVI_{30}$) ultimately decreased to 46 mL/g. The specific oxygen uptake rate decreased from an initial value 120.3 to a final value 70.7 mg $O_2/g$ $MLVSS{\cdot}hr$. Therefore, salinity injection affects the activity of AGS, causing degradation of the COD and nitrogen removal efficiency. It can be used as an indicator to objectively determine the effect of salinity on microbial activity.

• 한국산학기술학회논문지
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• 제16권1호
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• pp.900-905
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• 2015

본 Mn-Cu-$TiO_2$ Civil 촉매를 이용하여 질소산화물을 제거하는 $NH_3$-SCR 공정에서 소성조건 및 산소농도에 대한 영향을 연구하였다. 소성된 촉매시료를 사용하여 $H_2$-TPR 시스템에서 반응온도에 따른 수소전환특성을 조사하였으며, 소성조건에 대한 비표면적변화도 측정하였다. 실험결과 적합한 소성온도는 약 $300^{\circ}C$이며, 소성온도가 $500^{\circ}C$이상일 경우 Mn, Cu 성분의 저온활성이 크게 감소함을 알 수 있었다. SCR반응에서 기상산소는 중요한 반응변수이며 반응에 적합한 농도는 약 8vol%이었다.

• 한국습지학회지
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• 제19권4호
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• pp.508-514
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• 2017

부영양화로 인한 녹 적조류가 과잉 번식하여 다양한 환경문제를 야기해왔으나, 최근 조류를 에너지원으로 활용할 수 있는 바이오 디젤 연구가 활발하게 진행되고 있다. 특히 하수처리장의 산소공급을 위한 송풍에너지 절약을 위해 미세조류의 광합성 작용으로 발생하는 산소를 하수처리장에 적용시키는 연구도 다양하게 이루어지고 있다. 본 연구에서는 조류광합성 산소를 질산화에 필요한 산소로 활용하고자 실험실 규모의 조류-질산화 반응조를 운영하였으며, 운전구간은 크게 3구간으로 운전하였다. MLSS(Mixed Liquer Suspended Solid) 농도에 변화를 준 구간에서 24~38 %, Micro-algae 농도에 변화를 준 구간에서는 38~50%, 그리고 HRT(Hydraulic Retention Time)에 변화를 준 구간에서 61~80%의 암모니아성 질소 제거율이 나타났다. 연구결과 MLSS 가 감소함에 따라, Algae Biomass가 증가함에 따라 암모니아성 질소 제거율이 증가하는 경향을 보였으나, MLSS에 의한 영향보다 Algae biomass 에 의한 영향이 더 큰 것으로 나타났다.

• 생태와환경
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• 제35권2호통권98호
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• pp.133-140
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• 2002

본 연구는 실험실규모의 산화지 공법을 적용하였다. 체류시간 변화 및 산화지 형태가 처리율에 미치는 영향을 조사하였다. 조류의 광합성에 대한 유기물 제거율과 용존산소와의 상관관계는 야간에 비해 주간의 상관성이 더 높은 것으로 나타났고, 단일지의 경우는 체류시간 15일의 경우가 5일에 비해 상관성이 더 높은 것으로 조사되었다. 시간대별 DO변화는 체류시간 5일의 경우 다단산화지 내의 DO농포는 $42{\sim}19.8\;mg/l$를 나타내었고, 첫번째 조에 비해 후단으로 갈수록 높아졌다. 유기물 처리효율은 체류시간 5일이고, 4단 직렬식 다단 산화지 시설에서 제거효율이 더 높았다. 유기물 제거효율로 $TBOD_5$ 평균 제거율은 $49{\sim}83%$를 나타내었고, $SBOD_5$의 경우는 $87{\sim}92%$의 높은 처리율을 나타내었다. 또한 산화지내 조류생성량을 일정 농도로 유지시켜 주는 것이 산화지 공법의 처리율을 높일 수 있는 것으로 나타났다.