• 한국환경과학회지
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• 제20권12호
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• pp.1617-1624
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• 2011

Caustic (NaOH) solution is used to remove $H_2S$ from hydrocarbon streams in petroleum refining industry, gradually being, so called, spent sulfidic caustic (SSC) which has high levels of $H_2S$ and alkalinity. Thus, SSC can be used as an electron donor and a buffering agent for autotrophic denitrification. As SSC, however, contains some non-biodegradable organics, air stripping was conducted to remove the non-biodegradable organics. As a result, over 93 % of the non-biodegradable organics was removed within 30 min of aeration. Then, $Na_2S_2O_3{\cdot}5H_2O$, methanol and organic matters, which are produced from a biodiesel production plant, were added to reform the air-stripped SSC and their products being referred to new sulfidic caustics (NSCs) I, II and III, respectively. Thereafter, to investigate the effect of these products on the removal of COD and TN, these products were injected to a biological nitrogen removal (BNR) process, resulting in additional 44 % TN removal without noticeable increase in the effluent COD level. Therefore, it can be said that the BNR process is a promising option to treat NSC as demonstrated in this study whose results can be useful for developing resource recovery technologies.

• 대한환경공학회지
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• 제34권3호
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• pp.155-161
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• 2012

본 연구에서는 고순도 메탄을 회수하기 위해서 Plug Flow Reactor와 External $CO_2$ Stripper를 결합한 중온 Methane Enhancement System을 개발하였다. 반응조 운전인자로서 알칼리도와 Leachate 순환율(LRR, Leachate Recycle Rate)이 바이오가스의 조성과 생성량 및 TVS 제거효율에 미치는 영향을 규명하였다. 고순도 메탄회수 공정 운전결과 OLR 2 g TVS/L-d, 알칼리도 4 g/L as $CaCO_3$, Leachate 순환율 3 v/v-d일 때 평균 94%의 높은 메탄함량을 나타내 고순도 메탄회수를 위한 최적조건임이 밝혀졌다. 이때 1일 반응조 단위 부피당 0.71부피의 메탄이 생성되었으며, TVS 제거율은 79%로서 Control Reactor의 94% 수준을 달성하였다.

• 한국대기환경학회지
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• 제21권5호
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• pp.507-513
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• 2005

Increasing amounts of anthropogenic $CO_2$ emitted to the atmosphere are believed to be a significant factor in global climate change. Hence, the method of chemical absorption has been suggested to separate and recover acid gases such as $CO_2$. In this study, the characteristics of absorption and regeneration of $CO_2$ for the absorbent which adding HMDA (hexamethylenediamine) into AMP (2-amino-2-methyl-1-propanol), hindered amine, was investigated in lab-scale absorption/regeneration reactor. As a result of this study, the removal efficiency of $CO_2$ increased when adding $5.9\%,\;11.7\%\;and\;23.4\%$ HMDA into $30\%$ AMP respectively. Also, the removal efficiency of $CO_2$ increased $6.5\%,\;8.4\%,\;10.3\%$ respectively as compared to AMP alone when the gas flow rate was 7.5 SL/min. In addition, all absorbents used in the study revealed the high stripping efficiency, which was almost $99\%$, at the temperature of $110^{\circ}C$. Thus, the regeneration tower should be operated at $110^{\circ}C$. At this time, the concentration of exhausted $CO_2$ was higher than $99\%$.

• 자원리싸이클링
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• 제30권6호
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• pp.28-35
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• 2021

코발트와 니켈을 함유한 공정부산물 및 폐자원으로부터 Cyanex 301을 사용하여 코발트 및 니켈을 분리, 회수하는 실험을 실시하였다. 황산침출 모의 용액으로부터 10 v/v% Cyanex 301을 사용하여 추출할 경우, 리튬은 추출되지 않았으며, 평형 pH 1.5, 추출 상비(A/O) 1.0조건에서 마그네슘은 0.44%, 망간은 11.57% 추출되었으며 코발트와 니켈은 99% 이상 추출되었다. McCabe-Thiele diagram 분석 결과, 추출 상비(A/O) 2.0, 2단 추출을 통해 코발트와 니켈을 99.9% 이상 동시 추출 가능성을 확인하였다. 공추출 된 마그네슘 및 망간의 경우 세정 공정을 통해 제거가 가능하였는데, 세정액으로 0.05M 황산용액에서는 마그네슘은 99%, 망간은 87%이상 제거되었고, 세정액으로 0.05M 염산용액을 사용할 경우에는 마그네슘은 99.9%, 망간은 80% 이상 세정되어 제거 가능하였다. 세정 후 추출액에서 탈거 시에는 탈거액으로 3.0M 황산을 사용할 경우에는 코발트는 93%, 니켈은 5% 정도 탈거가 되어 선택적 탈거가 가능하였다. 그러나 8M HCl을 사용할 경우에는 코발트는 99.9% 이상, 니켈도 90% 이상 탈거되어 코발트와 니켈을 동시에 회수가 가능하였다.

• 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.

• 공업화학
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• 제5권1호
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• pp.90-98
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• 1994

구연산-초산-유산계에서 구연산의 반응추출에 영향을 미치는 여러 인자를 규명하기 위하여 추출제로 2급과 3급아민 및 용매화추출제를, 용매로 n-butylacetate, MIBK, kerosine 및 xylene 등을, modifier로서 tributyl-phosphate(TBP)와 isodecanol이 이용되었다. 그 외에 수용액상의 pH와, 온도의 영향을 연구하였고 평형상수도 얻었다. NaOH, $Na_2CO_3$ 및 $K_2HPO_4$ 알칼리 수용액에 의한 재추출 실험도 하였다. 실험결과 구연산의 추출에서 2급아민인 di-isotridecylamine(DITDA)이 추출도와 선택성에서 가장 좋았고 용매로서는 n-butylacetate가, modifier로서는 TBP가 우수하였다. 이외에도 수용액의 pH와 추출계의 온도가 낮을수록 추출도가 높았다. 재추출도는 stripping상의 염기도와 온도가 낮을수록 높아졌고 알카리 농도가 커질수록 높아졌다.

• Steel and Composite Structures
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• 제20권3호
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• pp.501-512
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• 2016

High-strength structural bolts have been utilized for beam-to-column connections in steel-framed structural buildings. Failure of these components may be caused by the bolt shank fracture or threads stripping-off, documented in the literature. Furthermore, these structural bolts are galvanized for corrosion resistance or quenched-and-tempered in the manufacturing process. This paper adopted the finite element simulation to demonstrate discrete mechanical performance for these bolts under tensile loading conditions, the coated and uncoated numerical model has been built up for two numerical integration methods: explicit and implicit. Experimental testing and numerical methods can fully approach the failure mechanism of these bolts and their ultimate load capacities. Comparison has also been conducted for two numerical integration methods, demonstrating that the explicit integration procedure is also suitable for solving quasi-static problems. Furthermore, by using precise bolt models in T-Stub, more accurately simulate the mechanical behavior of T-Stub, which will lay the foundation of the mechanical properties of steel bolted joints.

• 한국환경보건학회지
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• 제24권3호
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• pp.1-5
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• 1998

A spectrophotometric method was developed for the acidic solution stripped after an extraction of 0.5 to 2.5 ppm of Lead(II) from 50 mL of $Na_2S_2O_3$ solution into chloroform as the ion-pairs formed between their thiosulfate complexes and alkylamine, Aliquat336. Pb(II) in the stripped solution forms an complex with DDTC in pH 7.3 buffer solution, and was developed in yellow by copper replacement. The ydlow-colored solution have the maximum absorbance at 435 nm in the measurement of absorbance by UV-Visible spectrophotometer. The interference ions such as Fe(III), Hg (II), Al(III), Co, Cu, Ni, Zn, Ca, Sn, have great effects on the extraction, but they were overcomed by the usage of adequate masking agents before an extraction. At last, a good result was obtained in applying this method to synthetic water.

• 한국대기환경학회지
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• 제23권5호
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• pp.539-546
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• 2007

Increasing emission of $CO_2$ significantly effects the global warming. Chemical absorption is one of separation methods of $CO_2$ from the industrial flue gases. In this study, the $CO_2$ removal efficiency as well as the $CO_2$ absorption amount of aqueous AMP (2-amino-2-methyl-1-propanol) solutions were measured using the continuous absorption and regeneration apparatus. We investigated the effect of aqueous AMP+AEPD(2-amino-2-ethyl-1, 3-propanediol) and AMP+TIPA (triisopropanolamine) solutions to enhance absorption characteristics of AMP. As a result of this study, the absorption amount and $CO_2$ removal efficiency were increased with adding TIPA into 30 wt.% AMP. The absorption amount and $CO_2$ removal efficiency of aqueous 30 wt.% AMP+5 wt.% TIPA solution were $1.70\;kg-CO_2/kg-absorbent$ and 91.1%, while those of aqueous 30 wt.% AMP solution were $1.58\;kg-CO_2/kg-absorbent$ and 89.3%. In addition, aqueous 30 wt.% AMP+5 wt.% TIPA solution used in the study revealed the high stripping efficiency, which was almost 98%, at the temperature of $110^{\circ}C$. Thus, the temperature of regenerator should be operated at $110^{\circ}C$.

• 한국도로학회논문집
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• 제7권3호
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• pp.71-78
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• 2005

본 연구는 판유리 등의 생산 기초 원료인 소다회 $(Na_2CO_3)$ 생산 과정에서 발생되는 산업 부산물인 부산석회를 아스팔트 혼합물의 채움재로서 재활용 가능성을 검토하여 부산석회의 실질적인 활용 방안을 제시하고자 한다. 이를 위하여 부산석회를 기존의 석회석분 채움재에서 중량 대비 25%, 50%, 75%, 100%로 대체하여 제조한 아스팔트 혼합물에 대해 간접인장강도 시험, 회복탄성계수 시험, 수분 민감성 시험, 반복하중 간접인장 시험, 휠트래킹 시험을 실시하여 부산석회의 채움재 활용 가능성을 파악하였다. 또한 기존 석회석분 채움재를 사용한 아스팔트 혼합물과 소석회 (Hydrated Lime)를 사용한 아스팔트 혼합물의 공학적 특성을 비교 분석하여 부산석회를 재활용한 아스팔트 혼합물의 성능 증진 효과를 평가하고 본 기술의 실용화 가능성을 판단하였다.