• Korean Chemical Engineering Research
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• 제60권1호
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• pp.70-79
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• 2022

Biodiesel production has attracted attention as a sustainable source of fuel and is a competitive alternate to diesel engines. The glycerol that is produced as a by-product is generally discarded as waste and can be converted to green chemicals such as acetins to increase bio-diesel profitability. Acetins find application in fuel, food, pharmaceutical and leather industries. Batch experiments and analysis have been previously conducted for synthesis of acetins using glycerol esterification reaction aided by sulfated metal oxide catalysts (SO₄^2-/CeO₂-ZrO₂). The aim of this study was to optimize process parameters: effects of mole ratio of reactants (glycerol and acetic acid), catalyst concentration and reaction temperature to maximize glycerol conversion/acetin selectivity. The optimum conditions for this reaction were determined using response surface methodology (RSM) designed as per a five-level-three-factor central composite design (CCD). Statistica software 10 was used to analyze the experimental data obtained. The optimized conditions obtained were molar ratio - 1:12, catalyst concentration - 6 wt.% and temperature -90 ℃. A packed bed reactor was fabricated and column studies were performed using the optimized conditions. The breakthrough curve was analyzed.

• Carbon letters
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• 제11권1호
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• pp.13-21
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• 2010

Coconut shell activated carbon (CSAC) was investigated for its ability in the removal of two neutral chlorinated organic compounds, namely trichloroethylene (TCE) and dichloromethane (DCM) from aqueous solution using a packed bed column. The efficiency of the prepared activated carbon was also compared with a commercial activated carbon (CAC). The important design parameters such as flow rate and bed height were studied. In all the cases the lowest flow rate (5 mL/min) and the highest bed height (25 cm) resulted in maximum uptake and per cent removal. The experimental data were analysed using bed depth service time model (BDST) and Thomas model. The regeneration experiments including about five adsorption-desorption cycles were conducted. The suitable elutant selected from batch regeneration experiments (25% isopropyl alcohol) was used to desorb the loaded activated carbon in each cycle.

• Advances in environmental research
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• 제3권3호
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• pp.231-251
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• 2014

The present study examines the phosphate adsorption potential and behavior of mixture of Ground Burnt Patties (GBP), a solid waste generated from cooking fuel used in earthen stoves and Red Soil (RS), a natural substance in fixed bed column mode operation. The characterization of adsorbent was done by Proton Induced X-ray Emission (PIXE), and Proton Induced ${\gamma}$-ray Emission (PIGE) methods. The FTIR spectroscopy of spent adsorbent reveals the presence of absorbance peak at $1127cm^{-1}$ which appears due to P = O stretching, thus confirming phosphate adsorption. The effects of bed height (10, 15 and 20 cm), flow rate (2.5, 5 and 7.5 mL/min) and initial phosphate concentration (5 and 15 mg/L) on breakthrough curves were explored. Both the breakthrough and exhaustion time increased with increase in bed depth, decrease in flow rate and influent concentration. Thomas model, Yoon-Nelson model and Modified Dose Response model were used to fit the column adsorption data using nonlinear regression analysis while Bed Depth Service Time model followed linear regression analysis under different experimental condition to evaluate model parameters that are useful in scale up of the process. The values of correlation coefficient ($R^2$) and the Sum of Square Error (SSE) revealed the Modified Dose Response model as the best fitted model to the experimental data. The adsorbent mixture responded effectively to the desorption and reusability experiment. The results of this finding advocated that mixture of GBP and RS can be used as a low cost, highly efficient adsorbent for phosphate removal from aqueous solution.

• 한국식품과학회지
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• 제11권4호
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• pp.249-257
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• 1979

전보에서 저자들을 물리적 견고성이 우수한 포도당 이성화 효소를 세포 고정화 시킨 제품을 얻었다.(한국 식품 과학 회지, 11(No. 3), 192(1979). 이 효소 제품을 사용하여 실험실 조건에서 회분식 반응조와 충진식 반응조를 운영하여 효소의 반응 특성과 생산성, 활성 감소 현상을 비교 하였다. 본 고정화 효소의 비활성 역가는 회분식 반응조와 충진식 반응조에서 1 g당 각각 48 및 114 units였으며 연속적인 공정에서 더 높은 생산성과 이성화율을 보였다. 효소의 생산성은 체장 시간, 기질의 농도, 효소 부하율(附荷率) 및 반응조의 외형에 영향을 받았으며 충진 밀도가 450 g/l일 때 실제 공간율은 0.36이었으며 비교적 좋은 충진 현상을 보였다. 연속 공정중 효소의 활성 감퇴 현상을 고찰하기 위하여 2.5 M 포도당 용액을 체장 시간이 5.3시간이 되도록 약 220시간 동안 반응시켜 본 결과, 효소 활성 감퇴 곡선은 일차 반응을 따르며 활성 반감기는 115일로 연속 공정에 이용 가능함을 알았다. 이 고정화 효소 제품은 물리적 안정성이 높은 반면 물질 전달 계수가 반응 속도에 큰 영향을 미치는 것으로 나타났다.

• 분석과학
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• 제10권1호
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• pp.66-74
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• 1997

지름 2.54cm, 길이 10cm인 유리관에 tyrosinase(EC. 1.14.18.1)를 입자의 크기 $550{\mu}m$인 탄소에 고정시켜 충진하고, 페놀과 산소를 기질로 사용하여 tyrosinase의 반응 특성을 조사하기 위해 axial dispersion 모델을 제안하였다. 본 논문에서 페놀의 농도는 55.5mM로 고정시키고 산소(2.7ppm, 5.4ppm, 그리고 9.5ppm)와 유속 (1~3mL/s)을 변화시키면서 탄소에 고정된 tyrosinase의 반응을 관찰하였다. 또한, Damkolher수를 계산하고 분산 특성과 식으로부터 효소반응 속도 및 분산의 영향을 예측하기 위해 수치적 해석을 하였다. 연구 결과 물질저항은 주로 외부 전달과 내부확산이었으며, 제안된 모델에서 Biot수는 64.25였다. 페놀은 1.0mL/s 정도의 느린 속도에서 산소의 농도가 높을수록 높은 전환율을 나타내었다. 한편, axial dispersion 모델과 plug flow 모델의 비교에서는 모두 같은 전환율을 나타내어 axial dispersion 모델이 반응속도와 무관함을 알 수 있었다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권3호
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• pp.236-241
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• 2005

A decolorization process using ion exchange chromatography was developed to refine rhEGF as a cosmetic ingredient. A macroreticular resin (D314) was selected, with respect to its high decolorization rate and recovery yield of rhEGF, and the operational conditions of the decolorization process optimized. The optimum conditions were as follows: the rhEGF effluent was ion exchanged at a flow rate of 60.0mL/h, with an effluent pH 5.0, using a chromatographic column (i.d. 16mm) packed with D314, with a 7.5cm in bed height. The decolorization process was carried out under the optimum conditions, and halted when the effluent volume reached 350mL, giving a decolorization rate and recovery yield of rhEGF higher than 67 and $80\%$, respectively. When the decolorization rate exceeded $67\%$, the final product turned out to be white or light yellowish, which was to the satisfaction of the cosmetic standard.

• Current Research on Agriculture and Life Sciences
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• 제6권
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• pp.157-162
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• 1988

활성화시킨 Succinylaminopropyl glass beads에 glutaraldehyde을 사용하여 고정화시킨 Mucor spp L42 응유효소를 치즈 커드 형성과정에 이용하고져 고정화 효소의 안정성, 재이용성, 반응의 조건, 반응조의 형태등에 대하여 탈지유(pH 5.6, $8^{\circ}C$)를 사용하여 반응시킨후 $30^{\circ}C$ 항온수조내에서 커드의 형성 상태를 조사하였던바 다음과 같은 결과를 얻었다. 1) 고정화 Mucor spp L42 응유효소를 0.2M phosphate buffer(pH 4.6)에 0.06% sodium azide을 첨가한 액에 침지한 상태로 $5^{\circ}C$ 이하에서 보존할 경우 3개월 후에도 활력의 80%가 유지되었다. 2) 고정화 Mucor spp L42 응유효소를 탈지유(pH 5.6, $8^{\circ}C$)로 반응시켰을때 반응 초기에는 고정화 효소의 활력이 급격히 감소하였고, 이것은 bead에 결합되는 질소화합물과 효소의 활력간에 관계가 있는 것으로 나타났다. 3) 고정화 Mucor spp L42 응유효소에 bead와 탈지유의 접촉시간을 60 sec/ml로 하여 탈지유(pH 5.6, $8^{\circ}C$)로 연속적으로 반응시켰을때 6시간 이후에도 bead의 활력의 70%가 유지할 수 있었다. 4) Fluidized bed와 shaking fluidized bed을 사용하는 것이 충진반응조 보다 탈지유의 반응속도가 높았다.