• 공업화학
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• 제34권2호
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• pp.180-185
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• 2023

물의 전기 분해 효율을 향상시키기 위해 산소발생반응(OER)의 반응 속도를 가속화하며 고성능과 장기 안정성을 가진 OER 전기촉매 개발이 필수적이다. 본 연구에서는 고효율의 OER 전기촉매를 합성하기 위해 중공 금속-유기골격체 (MOF)로부터 유도된 루테늄-코발트 산화물 촉매를 개발하였다. 합성된 촉매는 루테늄의 표면 노출을 증대시킴으로 낮은 Tafel 기울기와 10 mA/cm²의 전류밀도에서 386 mV의 낮은 과전위가 관찰되었다. 또한 상용 RuO₂ 촉매 대비 높은 질량 활성과 안정성을 보여, 귀금속 촉매를 대체할 수 있을 것으로 기대된다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.251.2-251.2
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• 2010

Plant biomass has been proposed to be an alternative source for petroleum-based chemical compounds. Especially, phenolic chemical compounds can be obtained from lignin by chemical depolymerization processes because lignin consists of complex aromatic polymer such as trans-p-coumaryl, coniferyl and sinapyl alcohols, etc. Phenolic chemical compounds from lignin were usually produced in super critical water. However, we applied Near-critical water (NCW) system because NCW is known as a good solvent for lignin depolymerization. Organic matter like lignin can be solved in NCW system and the system has a unique acid-base property without conventional non-eco-friendly chemicals such as sulfuric acid and sodium hydroxide. In this work, we tried to optimize the NCW depolymerization system by adjusting the processing variables such as reaction time, temperature and pressure. Moreover, the amount of additional phenol was optimized by changing the molar ratio between water and phenol. Phenol was used as capping agent to prevent re-polymerization of active fragment such as formaldehyde. Alkali-lignin was used as a starting material and characterized by a Solid State 13C-NMR, FT-IR and EA (Elemental Analysis). GC-MS analysis confirmed that o-cresol, p-cresol, anisole and 4-hydroxyphathalic acid were the main product and they were quantitatively analyzed by HPLC.

• 약학회지
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• 제27권4호
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• pp.303-307
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• 1983

Pipethanate*HCl reacts with ammonium cobaltothiocyanate to form a stable ion pair which has an absorption maximum at 626nm. The reaction product was insoluble in water but freely soluble in most organic solvents. 1, 2-Dichloroethane was the best extracting solvent among the several organic solvents. Pipethanate*HCl can be determined not only by the spectrophotometry but also inderectly by estimation of cobalt in the organic phase by atomic absorption spectrophotometry. Linear relationship was found between absorbance and concentration in the range of $1.0{\times}10^{-3}~4.0{\times}10^{-3}M$ by spectrophotometry and $1.5{\times}10^{-4}~4.0{\times}10^{-4}M$ by atomic absorption spectrophotometry. With this method it was possible to determine pipethanate$\cdot$HCl in the pharmaceutical preparations.

• 멤브레인
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• 제6권2호
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• pp.101-108
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• 1996

반도성 세라믹 광촉매 막 반응기(membrane reactor)에 의한 난분해성 유독 유기물질의 효율적인 분해공정을 개발하기 위한 기초 연구로서 $TiO_{2}$ 광촉매 막의 전기화학 반응에 의한 개미산(formic acid)의 산화/분해 효율성에 대해 연구하였다. 막 반응기는 용액의 여과(filtration)와 광전기화학 반응에 의한 유기물의 광분해를 동시에 수행할 수 있도록 제작되었다. 복합막의 담체임과 동시에 전극의 역할을 할 수 있는 전기 전도성 $SnO_{2}$ 또는 stainless steel 다공성 튜브상에 pH가 1.45인 $TiO_{2}$ 졸을 졸-겔 침지 코팅하여 광촉매 복합막을 제조하였으며 광원으로는 365 nm 파장을 갖는 UV를 사용하였다. $TiO_{2}$ 광촉매 막의 전기화학 반응에 의한 개미산의 산화효율은 전극에 걸어주는 전압과 반응시간에 따라 증가하였으나 투과량(flux)에는 거의 무관하였다. $TiO_{2}/SnO_{2}$ 복합막을 사용한 경우 외부 전압을 27V 걸어주었을때 77% 정도의 산화효율을 얻을 수 있었으며 $TiO_{2}$/stainless steel 복합막에서는 90% 이상이었다. 광촉매 전기화학 반응을 이용함으로써 높은 투과량하에서도 개미산의 산화효율을 단순한 $TiO_{2}$ 광촉매 반응에서 보다 6~7배 가량 증진시킬 수 있었다.

• Environmental Engineering Research
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• 제23권4호
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• pp.345-353
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• 2018

This paper summarizes results of research on the electrochemical (EC) degradation of disinfection by-products (DBPs) and iodine-containing contrast media (ICMs), with the focus on EC reductive dehalogenation. The efficiency of EC dehalogenation of DBPs increases with the number of halogen atoms in an individual DBP species. EC reductive cleavage of bromine from parent DBPs is faster than that of chlorine. EC data and quantum chemical modeling indicate that the EC reduction of iodine-containing DBPs (I-DBPs) is characterized by the formation of active iodine that reacts with the organic substrate. The occurrence of ICMs has attracted attention due to their association with the generation of I-DBPs. Indirect EC oxidation of ICMs using anodes that produce reactive oxygen species can result in a complete degradation of these compounds yet I-DBPs are formed in the process. Reductive EC deiodination of ICMs is rapid and its overall rate is diffusion-controlled yet I-DBPs are also produced in this reaction. Further progress in practically feasible EC methods to remove DBPs, ICMs and other trace-level organic contaminants requires the development of novel electrocatalytic materials, elimination of mass transfer limitations via innovative design of 3D electrodes and EC reactors, and further progress in the understanding of intrinsic mechanisms of EC reactions of DBPs and TrOC at EC interfaces.

• 한국지반신소재학회논문집
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• 제22권4호
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• pp.35-42
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• 2023

본 연구에서는 유기오염물의 흡수가 가능한 차수재의 반응재료에 대하여 지중 매입 재료로서의 적용성을 평가하기 위해 오염물의 접촉에 의한 강도 특성 변화를 평가하였으며, 강도 평가는 일축압축시험 결과를 이용하였다. 시험 결과, 오염물 종류에 따른 반응재료의 강도는 물 > TCE > TPH의 순서로 확인되었다. 그러나 폴리노보넨의 구성비가 12% 이하에서는 TPH의 강도가 TCE에 비하여 크게 나타났다. 물로 접촉된 반응재료는 폴리노보넨의 구성비가 작을수록 강도가 지속적으로 감소하였지만, TCE 및 TPH와 접촉된 반응재료의 강도는 폴리노보넨의 구성비가 30%에서 21%까지 작아질수록 증가하다가 이후에는 감소하였다. 즉, 지중에서 발생되는 응력 조건에 따라 오염물의 접촉에 의한 강도를 고려하여 반응재료의 최적 구성비가 적용되어야 한다.

• Bulletin of the Korean Chemical Society
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• 제34권9호
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• pp.2577-2582
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• 2013

A novel stick-shaped portable sensing device featuring a microhole array interface between the polyvinylchloride-2-nitrophenyloctylether (PVC-NPOE) gel and water phase was developed for in-situ sensing of perchlorate ions in real water samples. Perchlorate sensitive sensing responses were obtained based on measuring the current changes with respect to the assisted transfer reaction of perchlorate ions by a perchlorate selective ligand namely, bis(dibenzoylmethanato)Ni(II) (Ni(DBM)2) across the polarized microhole array interface. Cyclic voltammetry was used to characterize the assisted transfer reaction of perchlorate ions by the $Ni(DBM)_2$ ligand when using the portable sensing device. The current response for the transfer of perchlorate anions by $Ni(DBM)_2$ across the micro-water/gel interface linearly increased as a function of the perchlorate ion concentration. The technique of differential pulse stripping voltammetry was also utilized to improve the sensitivity of the perchlorate anion detection down to 10 ppb. This was acquired by preconcentrating perchlorate anions in the gel layer by means of holding the ion transfer potential at 0 mV (vs. Ag/AgCl) for 30 s followed by stripping the complexed perchlorate ion with the ligand. The effect of various potential interfering anions on the perchlorate sensor was also investigated and showed an excellent selectivity over $Br^-$, $NO_2{^-}$, $NO_3{^-}$, $CO{_3}^{2^-}$, $CH_3COO^-$ and $SO{_4}^{2^-}$ ions. As a final demonstration, some regional water samples from the Sincheon river in Daegu city were analyzed and the data was verified with that of ion chromatography (IC) analysis from one of the Korean-certified water quality evaluation centers.

• KSBB Journal
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• 제6권3호
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• pp.281-288
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• 1991

This research was carried to investigate the effects of several organic solvents on the enzymatic transphosphatidylation in emulsion and two-phase solvent systems. The solvents having a similar dielectric constant with diethylether were effective for the enzyme activity. Diethylether and butylacetate were the most effective solvents, when added 12-15%(v/v) and 10-40%(v/v), respectively, for the synthesis of phosphatidylglycerol, phosphatidylethyleneglycol and phosphatidylpropyleneglycol. In the emulsion system, the size of ovolecithin liposome was increased and the clearness of the phospholipid bilayer was reduced as increasing the diethylether concentration. In the twophase solvent system, the rapidest reaction was obtained when water-organic solvent ratio was close to 1. The ratio of aqueous phase. however, should be lowered to 37% to gain the sole product of transphosphatidy1ation, without phosphatidohydrolysis.

• 한국지하수토양환경학회지:지하수토양환경
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• 제10권4호
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• pp.13-17
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• 2005

암모늄의 질산화 반응, 질소산화물의 탈질 반응, 그리고 유기물의 산화반응을 고려한 SAT 모델링 시스템에 대해서, 현장조건의 변화에 따른 모델 결과를 비교하기 위해 6가지 모델 조건에 대한 가상의 수직 2차원상 모델 시뮬레이션을 하였다. 시뮬레이션 조건에서 수리전도도, 주입수 주입율, 지표 피복 여부, 그리고 운영 계획과 같은 4가지 영향 인자들이 고려되었다. 시뮬레이션 결과, 모든 조건에서 모델 개발 과정에서 고려한 반응 영향들이 잘 모사되었다.

• 환경위생공학
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• 제10권1호
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• pp.98-105
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• 1995

In the treatment of wastewater or sewage plant sludge with high solid concentration, high rate digestion process in which heating and mixing occur at a time is mainly used, and in the case of wastewater containing solid matter below 1000mg/ℓ the recently developed AF or UASB is developed Recently and commonly utilized. But these processes have weakpoints such as clogging of packing media and need of long period of trial run after microorganism granulation. In this point of view, there are active researches on the ASBR( anaerobic sequence batch reaction ) that is capable of treating of organic matter with reactor that has no packing materials and controlling the inflow time, reaction time sedimentation time and outflow time by time control without loss of microorganisms. The objectives of this study are to evaluate the efficiency of ASBR process according to the reaction time, change of treated water quality and gas output rate in the treatment of wheat plant wastewater.