• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2002.10a
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• pp.153-153
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• 2002

수돗물의 염소소독 과정에서 부식질의 초기 분해생성물인 MX(Mutagen X)는 수돗물의 전체 돌연변이유발성의 최고 60%까지 차지하는 것으로 알려져 있다. 그러나 존재하는 농도는 수 ng/L로 정량분석을 위해서는 resin을 사용하여 10 ~ 20L의 물을 농축하여야 한다. 이 연구에서 MX의 농축에 사용된 resin은 XAD-4와 XAD-7HP의 1:1 mixture이었으며, 사용 전에 Soxhlet extractor를 사용하여 ethyl acetate와 methanol로 각각 12시간씩 세척하였다. 15L의 물 시료는 37%의 염산으로 pH 2에 맞춘 후 직경 2cm의 유리관에 15cm의 높이로 채워진 resin을 40mL/min의 유속으로 통과시켰다. 유리관에 잔류하는 물은 질소가스로 대부분 불어 제거한 후 ethyl acetate 200mL를 가해 1mL/min의 유속으로 흘려주어 MX를 용출시킨 후 회전증발기로 5mL의 부피까지 농축시키고 10% H$_2$SO$_4$ in MeOH 0.1mL를 가하여 6$0^{\circ}C$에서 methyl ester화하였다. 과포화된 $Na_2$SO$_4$ 수용액 0.3ml를 가한 후 MTBE 0.3mL로 추출하고 GC/ECD로 분석하였다. MX의 회수율은 60% 이상이었으며 일부수돗물 시료에 대해 분석하였다.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2015.10a
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• pp.441-442
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• 2015

• KSBB Journal
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• v.22 no.4
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• pp.197-200
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• 2007

This study examined the conditions of filtration and concentration of methanol extract from biomass. Filtration efficiency was improved by adding diatomaceous earth as a filter aid. The optimal amount of diatomaceous earth was 6% (w/w) to reduce the filtration time. The filtration time was reduced by 4.2% in first extraction, 30.0% in second extraction, 22.8% in third extraction, and 19.0% in fourth extraction, respectively. The optimal temperature of water bath was below 50$^{\circ}C$ for preventing paclitaxel degradation during concentration of methanol extract using a rotary evaporator. The temperature of concentrated solution in rotary evaporator was relatively low compared to bath temperature because of latent heat of evaporation. The stopping point of concentration in rotary evaporator for the following step was at a specific gravity of 0.96 of the concentrated solution in terms of the purity and yield of paclitaxel. This information is very useful for mass extraction of biomass for the recovery of paclitaxel from plant cell culture.

• Membrane Journal
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• v.9 no.4
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• pp.215-220
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• 1999

The asymmetric polyimide [PI] membrane with good solvent-resisting and heat-resisting properties was prepared by using the phase inversion method from polyamic acid, and its pervaporation separation characteristics of water-acetic acid system were studied. It was appeared from the prepared membranes that the best non-solvent of polyamie acid for the phase inversion was toluene. The best heat-treatment condition for the imidization of polyamic acid was 1 hr heating at each of the temperatures, 373, 473, and 573 K The thermal durability and chemical stability during the pervaporation separation of water-acetic acid of the prepared PI membrane was superior. The pervaporation characteristics of prepared membrane were 180 of separation factor and 0.5 kg/$m^2$hr of total flux for 80 wt% acetic acid feed.

• Membrane Journal
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• v.17 no.2
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• pp.146-160
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• 2007

A parametric study on pervaporation-facilitated esterification was performed by using a practical model based on non-perfect separation through membrane which is not perfectly permselective to water. Thus, membrane selectivity as well as membrane capability to remove water should be taken into account in establishing the simulation model to explain how the membrane separation influence the esterification reaction process. It was shown by simulation that in the reaction systems with non-perfect separation, the permeation of reactants which are acid or/and alcohol retards the reaction by inducing the backward reaction so that reaction conversion curve is located between a reaction system coupled with pervaporation process having a perfect permselectivity to water and a reaction system without pervaporation process. The volume change of reaction system occurs as a result of the permeation through the membrane. The reaction volume change which can be characterized by the reaction ratio of $r_{\Psi}\;to\;r_{{\Psi}=1}$ affects reaction kinetics by concentrating reactants and products, respectively, with different extent with time; reactant-concentrating effect is dominant during the initial stage of reaction, resulting in facilitating the reaction, and then product-concentrating effect is exerted more on reaction, causing to slow down the reaction. When pervaporative dehydration is applied to the reaction system plays an important role in the reaction as well. The effect of timing to impose pervaporation on reaction system affected the reaction kinetics in terms of reaction rate and reaction conversion. A relationship was derived to explain membrane unit capacity and reaction parameters that will be used as a design tool to determine membrane unit capacity at a given reaction conditions or reaction parameters at a membrane unit capacity.

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.826-837
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• 2015

In this study, we produced bioethanol from the original hydrolysate obtained during oxalic acid pretreatment of lignocellulosic biomass. The bioethanol was separated and concentrated by pervaporation and the residue after pervaporation was evaluated for its antioxidant activity. Xylose ($37.28g/{\ell}$) was the major product in the original hydrolysate. The original hydrolysate contained acetic acid, furfural and total phenolic compounds (TPC) as fermentation inhibitors. Acetic acid was removed by electrodialysis (ED), and $12.21g/{\ell}$ of bioethanol was produced from ED-treated hydrolysate. The TPC of ethyl acetate extracts from the residue obtained (OA-E) during pervaporation was 86.81 mg/100 g (extract). The $IC_{50}$ values of DPPH and ABTS radical scavenging activities, and reducing power of OA-E were $0.87mg/m{\ell}$, $0.85mg/m{\ell}$, and $0.59mg/m{\ell}$, respectively. Sugar degradation products and the phenolic compounds in OA-E were determined by GC-MS.

• Membrane Journal
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• v.4 no.3
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• pp.122-141
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• 1994

식품가공공장은 제품의 특성에 따라 필요로 되는 여러 가지의 단위공정이 조합되어 가동되고 있다. 식품제조 공정중 분리, 분획 및 농축은 매우 중요한 처리로 이를 위해서 증류, 증발, 원심분리, 여과 등의 조작이 절대적으로 필요하고, 최종 제품이 액상일 경우 유통중 변질 발생을 방지하기 위해 살균 공정을 반드시 거치도록 되어 있다. 또한 제품의 생산과정 중 사용되는 폐수에 의한 환경오염을 막기 위해서 폐수정화시설이 필수적으로 되어 있다. 이러한 대부분의 조작과정 중에는 열처리가 반드시 수반됨에 다라 가공원료 중에 함유된 각종 영양 성분이 부분적으로 열에 의해 파괴되고 냄새나 색 등이 변함에 따라 제품의 품질이 열화됨은 물론, 에너지 비용, 관련시설의 설치에 소요되는 부지, 시설비 및 운영비 등이 많이 필요로 된다.

• Proceedings of the Membrane Society of Korea Conference
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• 1995.10a
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• pp.33-35
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• 1995

현재 국내에서 생산되는 에탄올은 원료나 연료용으로 사용되는 합성알콜과 주류의 원료로 사용되는 발효알콜이 대부분을 차지하고 있다. 그러나 휘발유 첨가제, 연료용 알콜의 수요가 늘어날 경우 발효공정을 이용한 에탄올 연료의 사용이 늘어날 전망이며 특히 기존의 휘발유 첨가제 중 옥탄가 향상을 위한 MTBE 대신 에탄올, ETBE의 사용이 환경적인 측면이나 경제적으로 유리하다. 연로나 첨가제로서 에탄올을 사용하기 위해서는 기존의 95%의 순도를 갖는 일반에탄ㅇ올 대신에 99.5wt%이상의 고순도 에탄올을 생산하여야 하며 에탄올 농축공정 중의 하나인 Pervaporation은 국내에서 1-2년 전부터 연구가 활발히 진행되고 있으나 현재 국내에서 진행되고 있는 Pervaporation Test는 대부분 합성알콜을 이용하여 수행되었다. 이 실험에서는 주정공장에서 제조한 주정과 조주정을 이용, 현장 Pilot Test를 통해 PV System의 성능 검증, 에탄올 내 Trace 물질파악 및 필요 막면적을 이용하여 합성알콜과의 Performance비교를 수행하였다.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.10a
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• pp.143-145
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• 1998

식품공업 분야에서 특정 성분의 분리, 정제, 농축은 매우 중요한 단위공정으로써 추출(Extraction), 여과(Filtration), 증류(Distillation), 증발(Evaporation)등의 조작을 통하여 실시되고 있다. 최근 들어 화학공업, 기계공업, 식품공업의 지속적인 발전에 힘입어 단위조작을 효율적으로 실시할 수 있는 기술로써 국내의 산업화되고 있는 것이 분리막 기술이다. 현재 식품공업 분야에서 활용되고 있는 분리막공정의 종류는 정밀여과(Microfiltration), 한외여과(Ultrafiltration), 초정밀여과(Nanofiltration), 역삼투(Reverse Osmosis) 시스템으로 유제품, 조미료, 음료공업, 장유산업, 기능성 인자의 분리 등에 공업적으로 점차 그 도입 가능성이 증가하고 있다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.9
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• pp.595-603
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• 2011

In this study, an effort has been made to analyze the subcooled boiling heat transfer in a natural circulation vertical evaporator. To verify the analysis, a small-scale model was made and tested. The friction correlation by Ueda, void fraction and quality correlation by Saha and Zuber along with the superposition heat transfer model by Rohsenow yielded a satisfactory agreement with the model test data. The analysis was extended to simulate a 1 ton/day concentration system. Comparison with the test results of 1 ton/day prototype revealed that the data were overpredicted by 13%. The capacity of the prototype was 1.2 ton/day with COP of 5.77.