• 한국토양비료학회지
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• 제28권2호
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• pp.123-129
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• 1995

Zeolite 광석(鑛石)을 일정(一定) 크기의 입제(粒劑)로 제품화(製品化)하는 과정(過程)에서 생성(生成)되는 다량(多量)의 Zeolite 미분(微粉)의 부가가치(附加價値)를 높이기 위(爲)한 방법(方法)으로 Polyvinyl Alcohol(PVA)을 접착제(接着劑)로 이용(利用)하여 입단화(粒團化)시켰다. 이때에 입단화(粒團化)에 필요(必要)한 PVA의 적정농도(適定濃度)와 조제(調製)한 입상(粒狀)의 물리성(物理性)을 조사(調査)한 결과(結果)는 다음과 같다. 습식사별법(濕式篩別法)에 의(依)한 내수성(耐水性) 입단(粒團)의 함량(含量)은 PVA 0.3% 처리(處理)로 2.0mm 이상(以上)의 Zeolite 입단(粒團)이 98.0%였으며 0.6% 이상(以上) 처리시(處理時)는 거의 100%였다. PVA농도(濃度)가 증가(增加)할수록 수분침투속도(水分浸透速度)와 최대용수량(最大容水量)은 감소(減少)하였고 경도(硬度)는 증가(增加)하였으나 건조온도(乾燥溫度)에 따른 입단(粒團)의 물리성(物理性)에는 거의 변화(變化)가 없었다. Kaolinite와 Bentonite의 혼합비율(混合比率)이 증가(增加)함에 따라 경도(硬度)는 증가(增加)하였으며 이들은 수분함량(水分含量)이 증가(增加)할수록 경도(硬度)는 급격(急激)히 줄어들었다. Smectite와 Perlite의 혼합비율(混合比率)이 증가(增加)함에 따라 경도(硬度)는 낮아졌으나 수분침투속도(水分浸透速度)와 최대용수량(最大容水量)은 증가(增加)하였다.

• 한국막학회:학술대회논문집
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• 한국막학회 1993년도 추계 총회 및 학술발표회
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• pp.58-58
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• 1993

Pervaporation has become important as a method to separate liquid mixtures, sepecially azeotropic and close boiling-point mixtures. Especially, water-alcohol separations have been carried out a lot because of the practical interests in the industries. However, outstanding membranes with high selectivity and high permeability have not been available in common use yet. In order to separate selectively out the water mixed with alcohols with an aim of the purification of the alcohols, a membrane has tO have excellent affinity to water. Among the hydrophilic polymers, polyacrylic acid and poly(vinyl alcohol) are used widely. In recent years, ionomers and polyion complexes, better hydrophitic materials, start to be used. The polyion complex membranes, consisting of polyacrylic acid (PAA) and polycation, showed excellent permeation rates and selectivities. It was known that among the polycations, ioneries, which have quaternary ammonium groups in the backbone chain, were more effective in giving membranes of higher permselectivities. On this base, syntheses and characterizations of the polycations, with different chemical structures from the published ones, for the polyion complex membrane formation were studied in this paper.

• Bulletin of the Korean Chemical Society
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• 제9권1호
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• pp.1-4
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• 1988

Rates of solvolysis of trans-[Co$(N-eten)_2Cl_2$]$^+$ have been investigated using spectrophotometric method at various pressures and temperatures in the mixtures of water with the t-butyl alcohol which possesses a high structure inducing capacity in water. The values of ${\Delta}V^{\neq}$ obtained from pressure effect on the rate constants were 2.55∼ 5.83 $cm^3mol^{-1}$. These values were discussed in terms of dissociative mechanism. Extrema found in the variation of ${\Delta}H^{\neq}$ and ${\Delta}S^{\neq}$ with solvent composition correlated with extrema in the variation of the physical properties of the mixtures. The logarithms of rate constants correlated linearly with both Grunwald-Winstein parameter and the reciprocal of dielectric constant ($Ds^{-1}$). The gradient, m of Grunwald-Winstein plot for the trans-[Co$(N-eten)_2Cl_2$]$^+$ was 0.09, which is significantly lower than those for the other cobalt (Ⅲ)-dichloro complexes. It was suggested that the reaction is an Id mechanism with long extension of Co-Cl bond in the transition state, as found for the C-Cl bond in the transition state for the solvolysis of t-butyl chloride.

• 한국수산과학회지
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• 제1권2호
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• pp.135-137
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• 1968

1938년 A. F. Spillaus에 의하여 Bathythermograph가 고안된 이내 현재까지 수차 개량된 것이 제작판매하게 되어 해양조사 또는 어장탐색에 총중한 측기로 세계 각국에서 널리 보급되었다. 이 측기는 항해중이라도 수심 270m까지 내렸다 올림으로써 수심에 대한 수온이 동시에 연속된 일선으로 도은 또는 Smoked한 유리 판상에 기록되어 신속하게 수온의 미세한 수직분포를 알 수 있어 어장탐사에 필요한 나층의 판별과 그 수탐 및 수온의 판단에 큰 도움을 준다. 여기에서는 1, 2연전 이내 수산진흥원 산하 각 해구 시험소 및 교육기관을 비롯한 해양조사 관계기관에 다수양이 공급되어 널리 사용되고 있는 B.T의 Smoked-glass slide가 없어 사용의 곤란성 및 일본 또는 미국으로부터의 수입의 귀찮은 수속을 해소시키기 위하여 본원에서 실험 제작사용한 결과로서 간단하게 B.T Smoked glass Slide를 제작할 수 있는 방법을 소개하고자 한다.

• Bulletin of the Korean Chemical Society
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• 제23권8호
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• pp.1089-1096
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• 2002

Solvolyses rate constants of trimethylacetyl chloride (2), isobutyryl chloride (3), diphenylacetyl chloride (4) and p-methoxyphenylacetyl chloride (5) in 2,2,2-trifluoroethanol (TFE)-water, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP)-water and TFE-et hanol solvent systems at $10^{\circ}C$ are determined by a conductimetric method. Kinetic solvent isotope effects (KSIE) are reported from additional kinetic data for methanolyses of various substituted acetylchlorides in methanol According to the results of those reactions analyzed in terms of rate-rate profiles,extended Grunwald-Winstein type correlations, application of a third order reaction model based a general base catalyzed (GBC) and KSIE values. Regardless of the kind of neighboring groups (CH3- or Ph-groups) of reaction center, for aqueous fluorinated alcohol systems, solvolyses of 2, 3, 4, and 5 were exposed to the reaction with the same mechanism (a loose SN2 type mechanism by electrophilic solvation) controlled by a similarity of solvation of the transition sate (TS). Whereas, for TFE-ethanol solvent systems, the reactivity depended on whether substituted acetyl chloride have aromatic rings (Ph-) or alkyl groups (CH3-); the solvations by the predominant stoichiometric effect (third order reaction mechanism by GBC and/or by push-pull type) for Ph- groups (4 and 5) and the same solvation effects as those shown in TFE-water solvent systems for CH3- groups (2 and 3) were exhibited Such phenomena can be interpreted as having relevance to the inductive effect ( $\sigmaI)$ of substituted groups; the plot of log (KSIE) vs. ${\sigma}I$ parameter give an acceptable the linear correlation with r = 0.970 (slope = 0.44 $\pm$ 0.06, n = 5).

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권2호
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• pp.76-84
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• 2002

On-line conversion estimation of enzymatic esterification reactions in solvent-free media was investigated. In principle, conversion to ester can be determined from the amount of water produced by the reaction, because water is formed as a by-product in a stoichiometric manner. In this study, we estimated the water production rate only from some measurements of relative humidity and water balances without using any analytical methods. In order to test the performance of the on-line conversion estimation, the lipase-catalyzed esterification of n-capric acid and n-decal alcohol in solvent-free media was performed whilst controlling water activity at various values. The reaction conversions estimated on-line were similar to those determined by offline gas chromatographic analysis. However, when the water activity was controlled at higher values, discrepancies between the estimated conversion values and the measured values became significant. The deviation was found to be due to the inaccurate measurement of the water content in the reaction medium during the initial stages of the reaction. Using a digital filter, we were able to improve the accuracy of the on-line conversion estimation method considerably. Despite the simplicity of this method, the on-line estimated conversions were in good agreement with the off-line measured values.

• KSBB Journal
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• 제29권2호
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• pp.124-130
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• 2014

Acer tegmentosum was a traditional Korean herbal medicine showing various pharmacological activities. In this work, A. tegmentosum were extracted with boiling water and then successively partitioned with dichloromethane, ethyl acetate, n-butyl alcohol (n-BuOH), and water. Salidoside, the target compound, was purified in n-BuOH phase using a chromatography method. For the analysis of salidoside, TLC and LC-MS were used as well as on-line screening $HPLC-ABTS^+$ assay with three different wavelength of 254, 280, and 320 nm. An amount of 1.34 g of salidoside were obtained in n-BuOH phase fromAcer tegmentosum was a traditional Korean herbal medicine showing various pharmacological activities. In this work, A. tegmentosum were extracted with boiling water and then successively partitioned with dichloromethane, ethyl acetate, n-butyl alcohol (n-BuOH), and water. Salidoside, the target compound, was purified in n-BuOH phase using a chromatography method. For the analysis of salidoside, TLC and LC-MS were used as well as online screening $HPLC-ABTS^+$ assay with three different wavelength of 254, 280, and 320 nm. An amount of 1.34 g of salidoside were obtained in n-BuOH phase from 3 kg of dry biomass. The on-line screening $HPLC-ABTS^+$ assay is rapid and efficient tool to search bioactivity from A. tegmentosum. 3 kg of dry biomass. The on-line screening $HPLC-ABTS^+$ assay is rapid and efficient tool to search bioactivity from A. tegmentosum.

• 한국환경보건학회지
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• 제16권1호
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• pp.21-28
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• 1990

As a research for treatment of waste water by biological method, we investigated general characteristics of waste water and isolated some useful bacteria which effectively treated waste water. Compositions of waste water were analyzed to give COD 2060 ppm, PVA 560 ppm, T-N 50 ppm, T-P 3.3 ppm and PH 12. Also, we inverstigated optimum nutrients requirement and growth conditions by mixed culture as well as the effect of coagulants. The COD removal rate reached maximum state for 48 hrs culture at pH 7.0 and 30$^{\circ}$C. Alum as the coagulated was the most effective. The COD removal rate was also increased by supplementing 10 ppm phosphorous sources as additional nutrients. The COD of waste water was reduced to 10% of its initial value by the continuous culture. As a result of overall experiments the COD of effluents became about 100 ppm and final pH 7.

• 청정기술
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• 제24권3호
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• pp.239-248
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• 2018

본 연구에서는 (주)파인텍에서 개발한 제올라이트 4A 분리막을 이용하여 물, 에탄올, 이소프로필알코올 단일 성분 및 혼합물의 투과증발 실험을 수행하였다. 본 분리막은 수열합성법을 이용하여 제막하였고, Si/Al 비율이 1인 LTA 구조에 $Na^+$를 이온교환하여 약 $4{\AA}$의 기공크기를 갖고 있으며, 강한 친수성을 나타내고 있다. 물리적 특성을 확인하기 위해 SEM, porosimetry, BET, 압축강도계를 이용하였다. 다양한 온도 및 농도 조건 실험을 통해 제올라이트 4A 분리막이 물/에탄올(분리계수 3,000 이상) 및 물/이소프로필알코올(분리계수 1,500 이상) 혼합물로 부터 물을 선택적으로 분리할 수 있음을 확인하였다. 활동도계수, Generalized Maxwell Stefan 모형 및 Dusty Gas 모형을 이용하여 단일성분 및 혼합물의 투과증발 거동을 모사하였으며, Genetic Algorithm를 이용한 상수추정을 통하여 분리층의 흡착 및 확산상수를 구하였다.

• 한국대기환경학회지
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• 제29권1호
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• pp.97-104
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• 2013

Methyl alcohol is one of the basic intermediates in the chemical industry and is also being used as a fuel additive and as a clean burning fuel. In this study, conversion of carbon dioxide to methyl alcohol was investigated using catalytic chemical methods. Ceramic monoliths (M) with $400cell/in^2$ were used as catalyst supports. Monolith-supported CuO-ZnO catalysts were prepared by wash-coat method. The prepared catalysts were characterized by using ICP analysis, TEM images and XRD patterns. The catalytic activity for carbon dioxide hydrogenation to methyl alcohol was investigated using a flow-type reactor under various reaction temperature, pressure and contact time. In the preparation of monolith-supported CuO-ZnO catalysts by wash-coat method, proper concentration of precursors solution was 25.7% (w/v). The mixed crystal of CuO and ZnO was well supported on monolith. And it was known that more CuO component may be supported than ZnO component. Conversion of carbon dioxide was increased with increasing reaction temperature, but methyl alcohol selectivity was decreased. Optimum reaction temperature was about $250^{\circ}C$ under 20 atm because of the reverse water gas shift reaction. Maximum yield of methyl alcohol over CuO-ZnO/M catalyst was 5.1 mol% at $250^{\circ}C$ and 20 atm.