• 공업화학
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• 제8권4호
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• pp.679-684
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• 1997

석유화학공업에서 사용된 유동접촉분해(FCC) 폐촉매의 주성분은 Si와 Al이며, 그외에 Fe, Zn, Ti 등의 기본금속과 알칼리금속 및 Ce, Nd, Ni, V 등의 희유금속이 함유되어 있다. $0.25mo1/dm^3-H_2SO_4$를 침출제로 폐촉매를 침출하였을 때 Ce가 640, Nd가 310, 그리고 V가 $450mg/dm^3$ 함유된 pH 1.0의 침출액을 얻었고, 아미노인산형 킬레이트수지에 의하여 Ce와 Nd를 선택흡착시킨 후, $4.0mol/dm^3-HCl$로 용리시켜 $1.2g/dm^3$의 Ce와 $0.75 g/dm^3$의 Nd 농축액을 얻었다. 농축액을 다시 옥살산 침전 및 공기산화법으로 처리하여 Ce와 Nd의 분리가 가능하였으며, 염소이온 공존하에 추출제 TOPO를 이용한 용매추출법으로 V와 Al을 각각 분리시켜, FCC 폐촉매로부터 순도가 99%인 Ce, Nd 및 V의 분리정제가 가능하였다.

• Carbon letters
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• 제28권
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• pp.47-54
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• 2018

High surface carbon aerogels with hierarchical and tunable pore structure were prepared using ionic liquid as carbon precursor via a simple salt templating method. The as-prepared carbon aerogels were characterized by nitrogen sorption measurement and scanning electron microscopy. Through instant visual observation experiments, it was found that salt eutectics not only serve as solvents, porogens, and templates, but also play an important role of foaming agents in the preparation of carbon aerogels. When the pyrolyzing temperature rises from 800 to $1000^{\circ}C$, the higher temperature deepens the carbonization reaction further to form a nanoporous interconnected fractal structure and increase the contribution of super-micropores and small mesopores and improve the specific surface area and pore volume, while having few effects on the macropores. As the mass ratio of ionic liquid to salt eutectics drops from 55% to 15%, that is, the content of salt eutectics increases, the salt eutectics gradually aggregate from ion pairs, to clusters with minimal free energy, and finally to a continuous salt phase, leading to the formation of micropores, uniform mesopores, and macropores, respectively; these processes cause BET specific surface area initially to increase but subsequently to decrease. With the mass ratio of ionic liquids to salts at 35% and carbonization temperature at $900^{\circ}C$, the specific surface area of the resultant carbon aerogels reached $2309m^2g^{-1}$. By controlling the carbonization temperature and mass ratio of the raw materials, the hierarchically porous architecture of carbon aerogels can be tuned; this advantage will promote their use in the fields of electrodes and adsorption.

• 전기화학회지
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• 제12권3호
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• pp.287-294
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• 2009

$TiO_2$가 첨가된 탄소복합전극을 제조 Capacitive deionization(CDI)에서의 제염효과에 대하여 고찰하였다. 본 연구에서는 탄소전극과 탄소복합전극을 제조하여 순환전류전압법과 충전-방전 평가를 하였으며 이때의 이온제거율에 대하여 고찰하였다. 순환전류전압법으로 1 mV/s의 전위주사속도에서 측정한 결과 탄소전극은 125 F/g, 탄소복합전극의 축전용량은 243 F/g으로 2배 증가됨을 확인하였다. 탄소복합전극의 $TiO_2$의 함량은 10 wt.%로 고정하였으며 $TiO_2$가 첨가됨에 따라 전기이중층 흡착량이 증가되어 이온제거율이 탄소전극보다 25% 증가되었다.

• KSBB Journal
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• 제13권1호
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• pp.77-82
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• 1998

미생물 효소에 의해 생산된 생산모액 내의 글루타치온(L-${\gamma}$-glutamyl-L-cysteinylglycine, GSH)을 액체크로마토그래피를 이용하여 분리하였다. GSH와 결합하는 수지를 선택하기 위해 여러 수지와 GSH 수용액을 사용하여 회분식 흡착실험을 한 결과, pH 8.0에서 음이온 교환수지인 Q-sepharose와 QAE- sephadex에 GSH가 결합하였으나, QAE-sephadex는 수지와 결합된 GSH를 이탈시키기 위해 사용된 salt에 의해 부피가 줄어들어 부적합하였다. GSH 분리를 위한 기초실험을 위하여 GSH, cysteine, glutamate, glycine, $\gamma$-glutamylcysteine, ATP, glucose의 혼합액에서 GSH와 $\gamma$-glutamylcysteine를 다른 물질로부터 1차 분리할 수 있었다. NaCl의 농도를 조절하여 두 물질이 중첩되는 현상을 제거하여 분리하고자 하였으며, GSH의 tailing현상을 줄이도록 노력하였다. NaCl(35mM)을 용해시킨 Tris buffer를 사용함으로써 두 물질의 분리가 가능하였고, 생산모액을 사용하여 실험한 결과, 혼합 시료와 유사한 분리결과를 얻을 수 있었다. Standard solution에서의 GSH 분리결과 72.6%의 회수율을 보였으며, 생산 모액에서는 84.4%의 회수율을 각각 보였다.

• KSBB Journal
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• 제30권3호
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• pp.103-108
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• 2015

Production of foreign proteins by transgenic plant cell cultures has several advantages such as post-translational modification, low risk of product contamination and low-cost production and purification. However, target proteins are degraded by extracellular proteases existing in the media. A solution to this problem is the use of perfusion culture and ion exchange chromatography for the application of integrated bioprocess using in situ recovery. With this method, production of human granulocyte-macrophage colony-stimulating factor (hGM-CSF) was investigated in this study. First, optimization of cell concentration during the induction phase for the production of hGM-CSF was examined. As cell concentration increased, the level of hGM-CSF was decreased due to the presence of extracellular proteases. Induction using sugarfree media produced 33% more hGM-CSF. The effects of pH on the binding of hGM-CSF to cationic and anionic exchange resins were also investigated. In terms of stability, optimal pH was found to be 5~7. In the case of using buffer exchange when CM-Sepharose was used as a cationic exchange resin, optimal pH for binding was 4.8 and adsorption yield was 77%. When DEAE-Sepharose was used as an anionic exchange resin, it was 5.5 (74%). Without buffer exchange, optimal pH was 4.6 (84%). From these results, an integrated bioprocess using in situ recovery with simultaneous production and separation of foreign protein in transgenic plant cell suspension cultures was found to be feasible.

• 한국환경과학회지
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• 제18권11호
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• pp.1215-1224
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• 2009

This study evaluated the applicability of visible-light-driven N- and S-doped titanium dioxide($TiO_2$) for the control of low-level dimethyl sulfide(DMS) and dimethyl disulfide(DMDS). In addition, a photocatalytic unit(PU)-adsorption hybrid was evaluated in order to examine the removal of DMS and DMDS which exited the PU and a gaseous photocatalytic byproduct($SO_2$) which was generated during the photocatalytic processes. Fourier-Tranform-Infrared(FTIR) spectrum exhibited different surface characteristics among the three-types of catalysts. For the N- and S-doped $TiO_2$ powders, a shift of the absorbance spectrum towards the visible-light region was observed. The absorption edge for both the N- and S-doped $TiO_2$ was shifted to $\lambda$ 720 nm. The N-doped $TiO_2$ was superior to the S-doped $TiO_2$ in regards to DMS degradation. Under low input concentration(IC) conditions(0.039 and 0.027 ppm for DMS and DMDS, respectively), the N-doped $TiO_2$ revealed a high DMS removal efficiency(above 95%), but a gradual decreasing removal efficiency under high IC conditions(7.8 and 5.4 ppm for DMS and DMDS, respectively). Although the hybrid system exhibited a superior characteristic to PU alone regarding the removal efficiencies of both DMS and DMDS, this capability decreased during the course of a photocatalytic process under the high IC conditions. The present study identified the generation of sulfate ion on the catalyst surface and sulfur dioxide(maximum concentrations of 0.0019 and 0.0074 ppm for the photocatalytic processes of DMS and DMDS, respectively) in effluent gas of PU. However, this generation of $TiO_2$ would be an insignificant addition to indoor air quality levels.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2002년도 춘계 국제 학술대회
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• pp.23-25
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• 2002

This study was conducted to understand characteristics of wastewater which is discharged from small-scale dyehouse located in Seoul downtown area and to Find the appliable treatment method on the spot. The results of this study were summarized as followings. 1. The method which is used at present is mostly flocculation by coagulant or fenton oxidation. But the treatment efficiency of them are not good. 2. The results of fenton oxidation experiment demonstrated that treatment efficiency of COD was limited, which showed the need of the additional process or the improvement of existing treatment method, while the color was reduced considerably in optimal condition. 3. The optimal condition of fenton oxidation are as followings. -Feasible pH was in the 3∼4 regardless of the kinds of iron ions, But the fluctuation of treatment efficiency with the change of pH was small - The mass ratio of H$_2$O/CODcr was used to evaluate the parameter of H$_2$O$_2$ The optimal range of this was in 0.7∼1,3 and it was observed that the ratio got higher as the quality got worse. -For iron ion, FeCl$_2$4H$_2$O turned out to be more effective for removal of color compared with was compared FeSO$_4$7H$_2$Oin. the mass ratio of Fe/H$_2$O$_2$ of 2.3∼2.8 for of FeSO$_4$7H$_2$O and 1.6∼1.8 for FeCl$_2$4H$_2$O resulted in good treatment efficiencies. 4. With adsorption process applied before fenton oxidation in order to treat the high concentration wastewater, the treatment efficiency increased by 61％ in CODcr, 55％ in color. and if the power activated carbon is injected in more than 2500mg/$\ell$, the wastewater can be treated within the effluent quality criteria.

• 한국응용과학기술학회지
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• 제29권1호
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• pp.19-32
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• 2012

가교에 관한 리뷰논문으로 특허의 다수는 의료용이다. 조직공학용 지지체나 약물전달용 매체로 쓰이는 고분자의 가교는 세포 무독성, 제 자리 겔 형성성이 있는 가교반응을 중시하고 있다. 가교를 탄성률, 내약품성, 내열성의 증대 목적 외에 가교부위에 금속 흡착성, 방오성, 항균성, 이온교환성 등의 기능을 부여하고 있다. 환경의 자극에 응답하는 스마트 가교, 환경을 고려한 광 가교, 물리적 가교, 효소가교, 천연물 가교, 수성가교가 연구되고 있다. 120세 수명을 목표로 의용재료의 발전에 고분자 소재의 개발도 필수적이다. 가교를 통한 고분자의 기능성 부여 및 물성 강화도 더욱 섬세하게 될 것이다. 고분자 가교물 중의 중요한 분야를 점하는 히드로젤은 주사용 제자리 겔 형성성의 개선 방향으로 전개될 것이다. 코팅용 고분자 가교제는 작업자, 작업환경을 고려하여 저독성-무독성의 가교제, 낮은 에너지에서 가교되는 에너지 절약형 가교제가 개발될 것이다.

• 대한화학회지
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• 제35권5호
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• pp.553-559
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• 1991

$NH^{4+}$ retaining 이온으로 치환된 양이온교환 수지관에서 흡착시키는 희토류원소이온의 양, 수지관의 내경, 수지관의 길이 및 용리액의 pH 등을 변화시켜 용리시킨 후 용출액 중의 각 화학종을 분석하여 희토류원소이온의 용리 mechanism과 monazite 광에 포함된 희토류원소들의 분리에 관해 연구하였다. 인접한 희토류원소간의 분리능은 수지의 교환용량 이내에서는 흡착시키는 희토류원소이온의 양을 증가시킬수록 증가하였고, 내경이 같으면 수지관의 높이는 희토류원소이온의 분리능 및 분리시간에 영향을 미치지 않으며 희토류-EDTA 착물은 $NH^{4+}$형 수지에 흡착되지 않음을 알 수 있었다. 용리액의 pH는 수지관 내에서 희토류원소이온과 EDTA와의 반응성에 영향을 미쳐 분리에 큰 영향을 미쳤으며 pH가 낮을수록 분리능은 향상되나 분리시간이 길어짐을 알 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제22권1호
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• pp.58-68
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• 2012

An investigation was conducted on the enhancement of production and purification of an oxidant and SDS-stable alkaline protease (BHAP) secreted by an alkalophilic Bacillus horikoshii, which was screened from the body fluid of a unique Korean polychaeta (Periserrula leucophryna) living in the tidal mud flats of Kwangwha Island in the Korean West Sea. A prominent effect on BHAP production was obtained by adding 2% maltose, 1% sodium citrate, 0.8% NaCl, and 0.6% sodium carbonate to the culturing medium. The optimal medium for BHAP production contained (g/l) SBM, 15; casein, 10; $K_2HPO_4$, 2; $KH_2PO_4$, 2; maltose, 20; sodium citrate, 10; $MgSO_4$, 0.06; NaCl, 8; and $Na_2CO_3$, 6. A protease yield of approximately 56,000 U/ml was achieved using the optimized medium, which is an increase of approximately 5.5-fold compared with the previous optimization (10,050 U/ml). The BHAP was homogenously purified 34-fold with an overall recovery of 34% and a specific activity of 223,090 U/mg protein using adsorption with Diaion HPA75, hydrophobic interaction chromatography (HIC) on Phenyl-Sepharose, and ion-exchange chromatography on a DEAE- and CM-Sepharose column. The purified BHAP was determined a homogeneous by SDS-PAGE, with an apparent molecular mass of 28 kDa, and it showed extreme stability towards organic solvents, SDS, and oxidizing agents. The $K_m$ and $k_{cat}$ values were 78.7 ${\mu}M$ and $217.4s^{-1}$ for N-succinyl-Ala-Ala-Pro-Phe-pNA at $37^{\circ}C$ and pH 9, respectively. The inhibition profile exhibited by PMSF suggested that the protease from B. horikoshii belongs to the family of serine proteases. The BHAP, which showed high stability against SDS and $H_2O_2$, has significance for industrial application, such as additives in detergent and feed industries.