• Environmental Engineering Research
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• 제15권4호
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• pp.207-213
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• 2010

This study investigated the potential of using bottom ash to be used as an adsorbent for the removal of lead (Pb) from aqueous solutions. The physical and chemical characteristics of bottom ash were determined, with a series of leaching and adsorption experiments performed to evaluate the suitability of bottom ash as an adsorbent material. Trace elements were present, such as silicon and aluminum, indicating that the material had a good adsorption capacity. All heavy metals leached during the Korea standard leaching test (KSLT) passed the regulatory limits for safe disposal, while batch adsorption experiments showed that bottom ash was capable of adsorbing Pb (experimental $q_e$ = 0.05 mg/g), wherein the adsorption rate increased with decreasing particle size. The adsorption data were then fitted to kinetic models, including Lagergren first-order and Pseudo-second order, as well as the Elovich equation, and isotherm models, including the Langmuir, Freundlich and Dubinin-Radushkevich isotherms. The results showed that pseudo-second order kinetics was the most suitable model for describing the kinetic adsorption, while the Freundlich isotherm best represented the equilibrium sorption onto bottom ash. The maximum sorption capacity and energy of adsorption of bottom ash were 0.315 mg/g and 7.01 KJ/mol, respectively.

• 한국환경과학회지
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• 제25권12호
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• pp.1613-1622
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• 2016

Zeolite (FZ), prepared from fly ash, was immobilized with polyacrylonitrile (PAN) to fabricate PAN/FZ beads. The prepared PAN/FZ beads were characterized by scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The optimum ratio to prepare PAN/FZ beads was 0.3 g of PAN to 0.3 g of FZ. The diameter of the prepared PAN/FZ beads was about 3 mm. Sr and Cu ion adsorption experiments were conducted with PAN/FZ beads. A pseudo-second-order model fit the kinetic data for Sr and Cu ion adsorption by PAN/FZ beads well. The equilibrium data fitted well with the Langmuir isotherm model, and the maximum adsorption capacities were 96.5 mg/g and 74.6 mg/g for the Sr and Cu ions, respectively. Additionally, the values of thermodynamic parameters such as Gibbs free energy (${\Delta}G^o$), enthalpy (${\Delta}H^o$) and entropy (${\Delta}S^o$) were determined. The positive values of ${\Delta}H^o$ revealed the endothermic nature of the adsorption process and the negative values of ${\Delta}G^o$ were indicative of the spontaneity of the adsorption process.

• Journal of Chest Surgery
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• 제22권6호
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• pp.1025-1035
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• 1989

Since we first performed open heart surgery on December 30, 1986, 126 cases were operated on up to August 31, 1989. Among the 126 cases, 65 cases were congenital heart disease of which 63 were acyanotic disease, and 61 cases were acquired heart disease, most of which were valvular heart disease. The age distribution of congenital heart disease was from 1 years 2 months to 48 years, and males had a slightly higher incidence. The age of acquired heart disease was from a minimum of 15 years to a maximum of 68 years, and the male to female ratio was 1;1.5. Midsternotomy was performed in all cases, and the aortic cannula was inserted through ascending aorta and the venous cannula inserted into the SVC and IVC through the right atrium. Vent was inserted through the right superior pulmonary vein. Cardioplegia solution was used in all cases; it was composed of sodium bicarbonate 3.5 ampule, KCL 14 mEq, 2% lidocaine 2.5 ml, 20 % albumin 50 ml and heparin 1000 units mixed to 950 ml with Hartman solution, and was made to 4oC and infused 10 ml per Kg every 20 minutes. The congenital heart disease had a variety of VSD in 32 cases, ASD 23 cases, PS 6 cases, PDA 2 cases, and one case each of Ebsteins anomaly and tricuspid atresia. The operations performed for acquired heart disease were 4 cases of OMC, 33 cases of MVR, and 5 cases of AVR, and 1 case of AVR with CABG. DVR was perfomed in 13 cases, and triple valve replacement was done in 1 case. Other than these, excision of LA myxoma was 2 cases, and repair of traumatic VSD and removal of a pulmonary embolism were one case each. The surgical mortality was 5 cases[4%], all of which occurred in valve replacement cases. Follow-up study revealed 2 late deaths. One died after a traffic accident and one died due to sepsis after he had received a gastrectomy for ulcer bleeding. The remaining patients were in good condition.

• 한국식품과학회지
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• 제27권2호
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• pp.181-184
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• 1995

두유제조공정에서 부산물로 다량 발생하는 대두침출액으로부터 대두올리고당을 생산하기 위한 공정으로 한외여과의 적용가능성을 조사하였다. 차단분자량 20,000인 막을 사용하여 용적농축비 5.0 이상으로 한외여과할 경우 단백질을 약 40% 정도 제거할 수 있었으며 올리고당은 거의 전량을 여액으로 회수할 수 있었다. 제단백계수는 용적농축비 5.0 이상에서 완만하게 증가하기 시작한 반면 제당계수는 용적농축비 5.0에서 6.57%이었다가 용적농축비 10.0에서 19.95%로 급격하게 증가하는 양상을 나타내었다. 제거계수를 기준으로한 적정 용적농축비는 5.0이었다. 반면 대두올리고당의 회수율은 용적농축비 10.0에서 최대치를 나타내었다.

• 한국균학회지
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• 제40권4호
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• pp.254-257
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• 2012

경기도 지방의 된장 시료로부터 악취감소 효과 미생물 중에서 효모가 분리되었으며 rDNA염기서열분석에 의하여 Pichia farinosa로 동정 되었다. 공시균주 P. farinosa NASS-2로 대량배양조건 확립 및 미생물처리제를 제조하였다. 분리한 효모로 제조한 악취저감효과 처리제의 실내 시험결과 돈분에 미생물제를 처리하고 15일 경과 후 악취가스 감소율을 조사한 결과, 암모니아가스($NH_3$ gas)는 처리 전 19.49 ppm에서 처리 후는 1.38 ppm으로, 황화수소가스($H_2S$ gas)는 처리 전 5.89 ppb에서 처리 후는 0.32 ppb으로 감소하는 효과를 나타내었다. 일반적으로 박테리아가 악취저감효과 미생물로 사용되고 있으나 본 연구에서 사용한 된장에서 분리한 효모 특히 산막효모인 P. farinosa NASS-2의 악취효과(암모니아가스, 황화수소 가스)는 처음 보고이다.

• 대한수의학회지
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• 제32권4호
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• pp.677-681
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• 1992

This experiment was carried out to establish a proper method of indocyanine green(ICG) excrection test for a applicable liver function test in three Korean native cattle average weighing about 450kg and dairy cattle parity of 3~5. The results obtained the half life($T^1/_2$), fractional clearance rate(KICG), retention rate and plasma enzyme activities before or after injection of ICG were as follows. 1. The maximum absorbance of ICG in plasma was at 805nm. 2. Average half life and fractional clearance rate following the injection of ICG 0.25mg/kg body weight were $5.53{\pm}1.27$ minute and $0.131{\pm}0.031$/minute in Korean native cattle, $4.55{\pm}0.68$ minute and $0.156{\pm}0.031$/minute in dairy cattle, respectively. The ICG removal rate was exponentially liner for the first 15 minutes after injection both of Korean native cattle and dairy cattle. 3. Average plasma retention rate when 10, 15, 30 minutes after injection was $35.7{\pm}13.9$, $23.2{\pm}7.1$, $10.8{\pm}3.5%$ in Korean native cattle, $26.8{\pm}3.3$, $14.2{\pm}1.2$, $5.5{\pm}2.2%$ in dairy cattle, respectively. 4. Plasma enzyme activities(AST, ALT, r-GTP) were no variation among the before, during and after injection of ICG. From these results, ICG excretion test to cattle is applicable to evaluation of liver funtion in both clinical and research, and adopted the 15 minutes plasma sample as the sample taken at the ideal time for comparative purposes.

• 상하수도학회지
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• 제18권6호
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• pp.770-777
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• 2004

Three pilot-scale membrane systems were operated using lake water as influent in this study. Microfiltration (MF) membrane with pore size of 0.01 m was used in Systen I of which filtration mode was set at constant pressure of $1kgf/cm^2$. Ultrafiltration (UF) membranes with molecular cutoff (MWCO) of 80,000 and 13,000 were used in System II-1 and II-2, respectively. Constant flow mode was applied at the range between 0.7 and $1.5m^3/m^2{\cdot}d$ (average of $1.1m^3/m^2${\cdot}d) for System II-1 and between 0.37 and $1.65m^3/m^2{\cdot}d$ (average of $1.18m^3/m^2{\cdot}d$) for System II-2. In System I, the flux changed from $1m^3/m^2{\cdot}d$ to $0.2m^3/m^2{\cdot}d$ during the operation time of 5 months. System II showed recovery of 94% under the allowable maximum pressure of $3kgf/cm^2$ during the same operation period. From these results, the efficient operation was observed in constant flow mode with respect to filtration time and recovery. Average filtrate turbidity showed 0.0071 NTU in System I and 0.0054 NTU in System II, which implied that high turbidity removal was obtained in both MF and UF systems with no significant difference between MF and UF. From the fact that membrane flux depends largely on membrane type and operation mode, a guideline of optimum design and operation should be suggested for application of membrane systems to full scale water treatment.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.67-70
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• 2008

Biological conversion of biomass into fuels and chemicals requires hydrolysis of the polysaccharide fraction into monomeric sugars. Hydrolysis can be performed enzymatically, and with dilute or concentrate mineral acids. In this study, dilute sulfuric acid used as a catalyst for the hydrolysis of rapeseed straw. The purpose of this study is to optimize the hydrolysis process in a 15ml bomb tube reactor and investigate the effects of the acid concentration, temperature and reaction time on the hemicellulose removal and consequently on the production of sugars (xylose, glucose and arabinose) as well as on the formation of by-products (furfural, 5-hydroxymethylfurfural and acetic acid). Statistical analysis was based on a model composition corresponding to a $3^3$ orthogonal factorial design and employed the response surface methodology (RSM) to optimize the hydrolysis conditions, aiming to attain maximum xylose extraction from hemicellulose of rapeseed straw. The obtained optimum conditions were: acid concentration of 0.77%, temperature of $164^{\circ}C$ with a reaction time of 18min. Under these conditions, 75.94% of the total xylose was removed and the hydrolysate contained 0.65g $L^{-1}$ Glucose, 0.36g $L^{-1}$ Arabinose, 3.59g $L^{-1}$ Xylose, 0.51g $L^{-1}$ Furfural, 1.36g $L^{-1}$ Acetic acid, and 0.08g $L^{-1}$ 5-hydroxymethylfurfural.

• 공업화학
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• 제20권2호
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• pp.213-217
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• 2009

폐수처리와 동시에 전기를 생산할 수 있는 새로운 대체 에너지 기술로 주목받고 있는 미생물 연료전지(microbial fuel cell, MFC)는 혐기성 조건의 산화전극(anode)에서 미생물에 의한 촉매작용을 통해 유기물질을 분해하면서 화학에너지를 전기에너지로 전환시키는 장치이다. 본 연구에서는 MFC의 성능을 파악하기 위하여 도시하수를 사용하여 폐수처리 효율과 전기생산 특성을 평가하였다. 도시하수에 탄소원으로서 acetate를 주입하였을 때 COD 제거율은 75.7%에서 88.2%로 증가하였으며 전압은 0.22 V에서 0.4 V까지 급격하게 상승하였다. 다양한 외부저항 하에서 전기생산에 미치는 산화전극과 환원전극(cathode) 사이의 전극 거리에 대한 영향 및 산화전극의 표면적에 대한 영향을 조사하였다. 최고 전력밀도는 $610mW/m^2$이었으며, 전극간 거리가 가깝고 산화전극의 표면적이 작을수록 전기발생에 효과적임을 알 수 있었다.

• 분석과학
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• 제12권3호
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• pp.196-202
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• 1999

갈조류인 Sargassum horneri를 중금속 흡착제로 사용하여 중금속 Cd(II) 및 Pb(II)이온을 제거하였다. Sargassum horneri는 동해안에서 채취하였고, 풍건 건조시켜 40~60 mesh의 입자 크기로 흡착제를 만들어 사용하였다. batch법은 진탕 시간에 따른 흡착량을 측정함으로써 흡착속도를 조사하였고, column법은 해조 분말을 충진 시킨후 일정농도의 중금속용액을 1 mL/min의 속도로 흘려보내면서 흡착시키고 흡착량을 알아 보았다. 중금석 흡착에 미치는 pH의 영향은 batch법과 column법 모두, pH 10.5>7.0>3.5순으로 나타났다. Pb(II)이온이 Cd(II)이온보다 높은 흡착량을 보였다. 특히 batch법에서는 모든 pH의 조건하에서 5분이내에 최대 흡착량에 도달하였다. 회수율은 batch법에 의해 흡착된 중금속의 회수율이 column법에 의해 흡착된 중금속의 회수율 보다 조금 높게 나타났다.