• 한국물환경학회지
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• 제28권3호
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• pp.367-374
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• 2012

A flotation process has a shorter processing time and needs less space than a sedimentation process. Dissolved air flotation process (DAF) is an efficient flotation method and used in a conventional wastewater treatment process. However, DAF requires the circulation of water containing compressed air and requires expensive installation and operation cost. Plasma Air Flotation (PAF) process is able to float flocs by micro bubbles generated from underwater plasma without the circulation of bubbly water and additional saturators. Therefore, PAF can be an alternative solution overcoming economic barriers. In this study, Humic acid removal efficiency by PAF process was compared with that of sedimentation process. 44.67% and 87.3% reduction rate based on UV 254 absorbance has been measured in sedimentation and PAF respectively. In particular, PAF in the flocculation zone can dramatically remove humic acid from water. In flocculation zone, PAF can separate organic matters but sedimentation cannot.

• Bulletin of the Korean Chemical Society
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• 제21권9호
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• pp.855-859
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• 2000

An application of synergistic solvent extraction for the etermination of trace lithium in sea water has been studied by forming an adduct complex of thenoyltrifluoroacetone (TTA) and trioctylphosphine oxide (TOPO) in a solvent. The interference by major constituents in sea water was eliminated by phosphate precipitation. Ex-perimental conditions such as solution pH, concentrations of TTA and TOPO etc. were optimized in synthetic sea water with similar compositionto its natural counterpart. To eliminate the interference, 1.38g of ammoni-um dihydrogen phosphate and 2.5 mL of ammonia water were added into 100 mL of thediluted solution at $60^{\circ}C$ to form the phosphate precipitates of Ca2+ and Mg2+ ions. After the pH of this filtrate was adjusted to 8.0, 10.0 mL of m-xylene containing 0.1 M TTA and 0.05 M TOPO was added to the solution in a separatory funnel, and the solution was shaken vigorously for 20 minutes. The solvent was separated from the aqueous solution, and 20 uL of m-xylene solution was injected into a gaphite tube to measure the absorbance by GF-AAS. The detection limit was 0.42 ng/mL. Lithium was determined within the range of 146 to 221 ng/mLin Korean coast-al sea waters, and the recoveries in the spiked samples were 94 to 106%.

• 한국환경과학회지
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• 제7권1호
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• pp.104-111
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• 1998

The Dongbok lake water before and after alum coagulation and activated carbon adsorption were analyzed in terms of organic contents, molecular weight distributuin (MWD), and UV-absorbance. Dissolved organic compounds in the Dongbok lake were fractionated into three molecular size classes by gel permeation chromatography. The fractionation was reasonably successful in isolating compounds with The bulk of the dissolved carbon was present in compounds of molecular weight in the range of 3,000~10,000. Alum coagulation preferentially treated molecules of high molecular weight, which has molecules larger than 10,000. The dissolved organic carbon (DOC) removal after activated carbon adsorption was high in the Fraction B , IR . The $A_{260}$/DOC ratio after alum and activated carbon treatment the Fraction II, III. This results suggest that the organics remaining after each treatment has a trihalomethane formation potential

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.257-260
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• 2004

The durability and water - resisting capability of nuclear concrete structures can be greatly improved as the density of concrete surface increases. Applying the surface penetration sealer to the concrete surface can increase the surface density. Therefore, the objective of this study is to identify the most suitable surface penetration sealer based on lab test. The considered parameters rate and water resistance and absorbance rate of the concrete specimen after the penetration sealer are applied. The experimental study resulted in the identification of the two most suitable surface penetration sealer based on their performance.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 춘계학술대회
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• pp.263-264
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• 2021

산업화의 변화와 환경파괴에 영향중 음용수 수질의 평가 및 관리의 중요성이 대두되고 있다. 현재 우리나라의 탁도에 관한 법 규제가 되어 공정관리에 있어 1.0NTU이하의 저농도 탁도를 유지해야하며, 제어 기술이 필요한 과제로 남아있다. 본 연구는 470nm, 670nm, 850nm를 이용하여 탁도에 따른 흡광도 실험을 하였으며, 850nm의 광원과, 820nm의 수광소자를 이용하여 시료의 90,180도와 따른 반사과 투사광의 관계와 입사광과 수광부의 높이차를 두어 산란광의 영향에 대해 실험을 하였다.

• 대한환경공학회지
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• 제22권3호
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• pp.441-451
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• 2000

정수장에서 발생하는 슬러지에는 처리과정에서 주입되는 응집제로 인하여 다량의 알루미늄 성분이 함유되어 있으며, 정수장에서 널리 사용되고 있는 폴리염화알루미늄(PACI) 응집제의 원료는 전량 수입되고 있는 실정이다. 본 연구는 정수 슬러지의 효과적인 재활용을 목적으로 수행되었다. 슬러지내의 알루미늄 성분을 염산(HCI)으로 용출하고 HCI 가스를 주입하여 염화알루미늄수화물($AlCl_3{\cdot}6H_2O$)을 제조하였다. 그리고 저온($180^{\circ}C$)에서 열분해시켜 고체상태의 염기성 염화알루미늄 [$Al(OH)_xCl_{3-x}$]을 얻은 후 이것을 물에 용해시켜 PACl(Polyaluminum chloride)을 제조하였다. 슬러지 용출 실험 결과 반응시간 10분, 반응온도 $105^{\circ}C$, 염산농도 27.65wt%에서 최적 용출율을 얻을 수 있었으며, KS 규격실험 결과 순도 98.7% 이상의 염화알루미늄수화물($AlCl_3{\cdot}6H_2O$)을 제조할 수 있었다. 제조된 PACl 응집제($PACl_{re}$)는 KS 규격을 모두 만족하였고, 열분해시 최적 열분해 온도는 $180^{\circ}C$이며 이때 염기도는 열분해율에 의해 결정되었다. 제조된 PACI 응집제($PACl_{re}$)와 기존의 PACI 응집제(PACI)의 성능비교 실험 결과, 탁도, DOC, $UV_{254}$ chlorophyll-a에서 유사한 효과를 보이는 것으로 나타났다.

• 동아시아식생활학회지
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• 제17권3호
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• pp.402-408
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• 2007

최근 식품 및 천연 물질로부터 항산화 작용이 있는 생리 활성 물질을 찾고자 하는 연구가 활발하게 진행되고 있다. 본 연구에서는 우리나라를 비롯하여 동양권에서 전통적으로 자양강장을 목적으로 많이 사용해온 인삼을 압출 성형 기술에 의해 가공한 후 80% 에탄올로 추출하고 감압 농축한 에탄올엑기스와 이를 에테르를 이용하여 지방 성분을 제거한 후 수포화 부탄올 처리한 부탄올 분획과 물 분획을 얻었다. 인삼과 압출 성형 인삼의 부탄올 층을 각각 고속 액체 크로마토그라피에 의해 인삼 사포닌 함량을 측정하였다. 실험 결과 압출성형 인삼이 대조 인삼에 비해 ginsenoside Rg1의 경우 약 2.2배, Re의 경우 약 2.3배, Rc의 경우 약 1.2배, Rb2의 경우 약 1.3배, Rd의 경우 약 2.2배의 사포닌 함량이 증가하는 결과를 보였다. 또한, ORAC 방법에 의한 항산화 활성 실험 결과, 압출 성형 인삼의 경우 인삼 중의 여러 유효 성분이 많이 함유되어 있는 80% 에탄올 추출분 획과 일반적으로 사포닌 성분을 많이 함유한 부탄올 분획은 물론이고, 사포닌 함량이 거의 없는 수층 분획 모두에서 대조 인삼의 분획들에 비해 유의성 있는 증가 (0.05

• 센서학회지
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• 제23권4호
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• pp.272-277
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• 2014

At present, the index of chemical oxygen demand (COD) is widely used as an indicator of organic water pollution with biochemical oxygen demand (BOD). But, traditional COD measurement method are not only with various chemical reagents exhausted, but also long time consumed, the operation procedure and the modification are much professional. This paper reported a novel COD measurement system using double-beam and multiple wavelength analysis UV-VIS spectrometries. It consists of pulsed xenon lamp, two-way optical fiber, optical switch, spectrometer and main processor. Proposed COD measurement system obtains any spectral information of water sample (KHP standard sample and two river water and wastewater) and reference sample (distilled water) in the range of 200~520 nm, corresponding to the COD concentration from 0 to 300 mg/L through calculating the UV absorbance. The system show improved precision and can work continuously fast at time interval about 25 seconds.

• 한국환경과학회지
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• 제23권5호
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• pp.985-993
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• 2014

For the field application of dielectric barrier discharge plasma reactor, a multi-plasma reactor was investigated for the inactivation of microorganisms in sewage. We also considered the possibility of degradation of non-biodegradable matter ($UV_{254}$) and total organic carbon (TOC) in sewage. The multi-plasma reactor in this study was divided into high voltage neon transformers, gas supply unit and three plasma modules (consist of discharge, ground electrode and quartz dielectric tube). The experimental results showed that the inactivation of microorganisms with treated water type ranked in the following order: distilled water > synthetic sewage effluent >> real sewage effluent. The dissolved various components in the real sewage effluent highly influenced the performance of the inactivation of microorganisms. After continuous plasma treatment for 10 min at 180 V, residual microorganisms appeared below 2 log and $UV_{254}$ absorbance (showing a non-biodegradable substance in water) and TOC removal rate were 27.5% and 8.5%, respectively. Therefore, when the sewage effluent is treated with plasma, it can be expected the inactivation of microorganisms and additional improvement of water quality. It was observed that the $NH_4{^+}$-N and $PO{_4}^{3-}$-P concentrations of sewage was kept at the constant plasma discharging for 30 min. On the other hand, $NO_3{^-}$-N concentration was increased with proceeding of the plasma discharge.

• 상하수도학회지
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• 제21권2호
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• pp.195-201
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• 2007

A submerged flat-sheet membrane separation system integrated with PAC (powdered activated carbon) was used in this research in order to investigate the effects of PAC on the efficiencies of operation and treatment and to evaluate the performance of the system. The experiments were carried out under operating conditions of a filtration rate of 0.38 m/d, water temperature of $20-28^{\circ}C$, and PAC dose of 0 g/L (Run-A) and 20 g/L (Run-B). The influent concentrations of TOC (total organic carbon), $NH_4{^+}-N$ (ammonia nitrogen) and $UV_{254}$ (UV absorbance at 254 nm) were 2.48 mg/L, 1.4 mg/L and 2.53 1/m, respectively. TOC removal of 43.2 and 73.6%, ammonia nitrogen removal of 4.9 and 15.9%, and $UV_{254}$ removal of 20.6 and 31.6% were obtained for Run-A and Run-B, respectively. During an experimental period of 33 days, no change was found in TMP (Run-B), but the TMP in Run-A increased by 5 kPa after 29 days. This research showed that the filtrate quality and the performance efficiency were enhanced when PAC was introduced into the filtration system.