관형 PDMS/세라믹 복합막을 이용한 이소프로판올 수용액의 투과증발 특성

홍원희,홍연기 한국화학공학회 1998 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.36 No.4

적절한 선택도를 유지하면서 투과도를 향상시키기 위해 기존의 실리콘(PDMS)막을 세라믹 지지체에 코팅한 복합막을 사용하여 이소프로판올 수용액에 대한 투과증발 실험을 수행하였다. 이소프로판올 수용액에서의 투과증발 실험에서 이소프로판올의 선택도는 공급액에서의 이소프로판올의 농도에 따라 감소했으며 투과량은 증가하였다. 조업온도의 영향은 세라믹 지지체와 복합된 실리콘막을 사용했을 경우에는 물이 많은 공급액의 농도영역(0-20wt% 이소프로판올 수용액)에서는 조업온도에 따라서 선택도가 증가하는 것으로 나타났다. 이는 투과하는 물과 세라믹 지지체 사이의 강한 인력 즉, 투과하는 물의 모세관 응축으로서 설명이 가능하다. 이러한 현상은 세라믹 지지체의 강한 친수성에 근거한다. 공급액에서의 물의 농도가 줄어들수록 온도에 따라서 선택도는 감소하는 것으로 나타났다. 지지체의 유무에 따른 투과증발 특성의 차이를 고찰하기 위해서 지지체가 없는 단일한 실리콘막을 이용하여 투과증발 실험을 수행하였다. 지지체가 없는 경우 선택도는 조업온도가 상승할수록 감소한다는 일반적인 경향을 따랐다. PDMS(Polydimethylsiloxane)/ceramic composite membrane was used in pervaporation process in order to enhance the flux with maintaining proper selectivity. In pervaporation of IPA(Isopropanol) from aqueous IPA solution, selectivities of IPA decreased and fluxes increased with concentration of IPA in feed mixtures. in removal of IPA from aqueous IPA solution by using PDMS/ceramic composite membrane, selectivities of IPA increased with operating temperature in the range from 0 to 20wt% of IPA, in feed mixtures. This phenomenon could be explained in terms of coupling effects between permeant and composite membrani and between permeants. Among these effects, capillary condensation could be importantly considered due to hydrophilicity and porous structure of ceramic support. In order to investigate the effect of ceramic support on pervaporation characteristics, pervaporation with homogeneous PDMS membrane without ceramic support was carried out with the same feed mixtures. In the case of non-support membrane, the selectivities of IPA decreased with operating temperature in all the concentration range of IPA in feed mixtures.

Effective Extraction of Oligomeric Proanthocyanidin (OPC) from Wild Grape Seeds

홍원희,허윤석,Tae Hee Hong 한국생물공학회 2004 Biotechnology and Bioprocess Engineering Vol.9 No.6

The Oligomeric proanthocyanidin (OPC) in green and black tea, grape seeds, grapes and wine has raised much attention but that OPC in wild grape seed remains to be intensively investigated. This study investigated the total OPC contents and total antioxidant activity of wild grape seeds and developed an efficient extraction process with various temperatures, solvent compositions and times. Also, a chromatography column packed with the Dia-ion HP-20 resin was used for further purification of the OPC. The total OPC contents were determined with the Folin-Ciocalteu reagent, and the antioxidant activity using total antioxidant potential (TAP) and 1,1-diphenyl-2picrylhydrazyl (DPPH). The yield of final purified OPC was 1.78 (+)-catechin equivalent (CE) g/100 g, with IC50 activities of TAP and DPPH of 31.60 and 15.70 g/mL. These activities of the final purified OPC were about two times higher than that of the BHA used as a reference sample.

Effect of Salts on the Extraction Characteristics of Succinic Acid by Predispersed Solvent Extraction

홍원희,홍연기,Bong Seock Kim 한국생물공학회 2004 Biotechnology and Bioprocess Engineering Vol.9 No.3

Predispersed solvent extraction (PDSE) of succinic acid with Tri-n-octylamine (TOA) dissolved in 1-octanol from aqueous solutions of 50 g/L succinic acid was examined. It was found that the equilibrium data in PDSE was equal to that in conventional solvent extraction in spite of the lack of mechanical mixing in PDSE. The influence of salts on succinic acid extraction and the stability of colloidal liquid aphrons (CLAs) were also investigated. Results indicated that in the presence of sodium chloride, less succinic acid was extracted by CLAs and the stability of CLAs decreased. However, the stability of CLAs was sufficient to make PDSE practically applicable to real fermentation broth, considering the concentration range of salts in the fermentation process for succinic acid.

96 하계특별심포지움을 마치고

홍원희 한국화학공학회 1996 NICE Vol.14 No.5

Predispersed Solvent Extraction of Succinic Acid Aqueous Solution by Colloidal Liquid Aphrons in Column

홍원희,홍연기,허윤석,Bong Seock Kim 한국생물공학회 2004 Biotechnology and Bioprocess Engineering Vol.9 No.6

A study of the PDSE (predispersed solvent extraction) for succinic acid by colloidal liquid aphrons was conducted. The organic phase contaning TOA (tri-n-octylamine) and 1-octanol permits a selective extraction of succinic acid from its aqueous solution. There was no difference of the extractability of PDSE and that of conventional mixer-settler type extraction. Taking into account the no mechanical mixing in PDSE, it was concluded that the PDSE process is more adaptive than the conventional mixer-settler type extraction process. From mass transfer analysis at the various concentration of TOA in counter-current continuous operation, the concentration of TOA had no influence on the mass transfer coefficient. The loading values in continuous PDSE were almost same as those in batch operation.

효율적 숙신산 생산을 위한 다양한 아민추출제와 용매를 이용한 아세트산의 선택적 추출제거

홍원희,홍연기,허윤석,전영시 한국생물공학회 2005 KSBB Journal Vol.20 No.3

Succinic acid has recently been drawing much interest as a raw material for biodegradable polymer. In this study acetic acid was removed by reactive extraction with various amines dissolved in various diluents. Distribution coefficients were determined as the kind of amines, diluents, and pHs of continuous phase. The extraction capacity increased with the polarity of diluent and the decrease of pH from the artificial binary solution. Based on the different extractability for succinic acid and acetic acid from the artificial binary solution, the removal of acetic acid from fermentation broth was investigated using various amines and diluents. In addition, the extractability and selectivity of CLA for succinic acid and acetic acid from fermentation broth were higher than that of straight solvent extraction. 최근 들어 카르복실산 중에서 숙신산은 생분해성 고분자의 원료물질로서 주목받고 있다. 본 연구에서는 다양한 아민추출제 및 희석제를 이용한 반응추출을 통해 숙신산 및 아세트산의 선택추출에 대한 연구를 하였다. 그 결과 활성희석제의 경우 2, 3차 아민의 추출능이 우수하였고, 비활성희석제의 경우에는 4차 아민의 추출능이 보다 높게 나타났다. 전체적인 분배계수 값을 비교할 때 활성희석제를 이용한 반응추출이 효과적임을 알 수 있었다. 또한 실제 발효액을 이용한 반응추출 실험결과, 모사 수용액에 비하여 추출능이 현저히 감소함을 볼 수 있었는데 이는 발효액에 들어있는 여러 가지 불순물들이 반응추출을 저해하기 때문이다. 여러 불순물들에 대한 반응추출의 저해 영향은 아세트산에 비해 숙신산이 컸으며, 이를 통해 실제 발효액에서 숙신산을 정제하기 위해서는 불순물로 존재하는 아세트산을 선택적으로 추출하여 제거하는 분리공정을 적용하는 것이 효과적임을 알 수 있었다. 추출제의 물질전달 및 보다 빠른 반응성의 향상을 위해 CLA에 대한 분배계수 및 선택도 실험을 수행한 결과, pH 변화에 따라 분배계수 및 선택도가 증가함을 알 수 있었다.

학회소식

홍원희 한국화학공학회 1990 NICE Vol.8 No.3

막증류 공정에서 소수성 막의 특성이 투과플럭스와 한계조업온도에 미치는 영향

홍원희,이철행 한국화학공학회 1998 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.36 No.6

진동밑에 의한 나노페이즈 타이타니아 분말의 제조

홍원희,이인식,박승빈,최시경,최동구 한국화학공학회 1997 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.35 No.3

진동밀에 의한 분쇄가 TiO₂분말의 특성에 미치는 영향에 관하여 조사함으로써, 나노페이즈 타이타니아 입자의 제조 가능성을 검토하였다. 평균 입자 크기는 분쇄전 3.42㎛에서 분쇄 초기에는 크게 감소하다가 0.2㎛의 일정한 값에 접근하였으며, 입도 분포는 분쇄 시간이 길어질수록 점차 좁은 분포를 가졌다. X선 회절 도형 관찰 결과 분쇄 시간에 따라 회절선의 폭이 점점 넓어짐이 관찰되었다. 결정자의 크기는 분쇄전의 600㎚에서 분쇄초기에 급속히 감소하다가 대략 20 ㎚에 접근하는 반면, 불균일 변형률은 분쇄 시간에 따라 계속 증가하는 경향을 보임을 알 수 있었다. 따라서, TiO₂ 분말을 진동밀에서 분쇄하여 나노페이즈 크기의 분말을 제조할 수 있음을 확인할 수 있었다. The possibility of preparing nanophase titania powder was examined by investigating the effect of vibratory milling on the characteristics of TiO₂ powder. The starting powder with a mean particle size of 3.42㎛ showed a fast rate of particle-size-reduction at the early stage of milling. By further milling, the milling rate decreased significantly and the mean particle size approached a constant value of 0.2 ㎛. Prolonged milling produced narrower particle size distribution. According to XRD results, it was observed that the diffraction lines became broader with increasing milling time. The crystallite size of 600 ㎚ at a starting powder decreased rapidly at the early stage of milling and it approached nanophase region of about 20 ㎚. Nonuniform strain increased continuously with milling time. The results show that nanophase titania powder was prepared by vibratory milling.

Influence of Chain Length of Tertiary Amines on Extractability and Chemical Interactions in Reactive Extraction of Succinic Acid

홍원희,홍연기 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.2

Reactive extraction of succinic acid from aqueous solutions with various tertiary amines dissolved in 1- octanol and in n-heptane has been studied as a function of the chain length of the tertiary amine. In the tertiary amine extractants in 1-octanol, the extractabilities of tertiary amines were proportional to their chain length. But, in n-heptane, the extractabilities of tertiary amines decreased with their chain length. In order to analyze chemical interactions involved in the complexation of succinic acid with amine extractants in 1-octanol and n-heptane, infrared (IR) spectroscopy was used. From IR spectroscopy, it was found that the difference of extractability in 1-octanol and in n-heptane was mainly due to the different degree of intramolecular hydrogen bonding of succinic acid with the polarity of diluents. And the possible stoichiometry of acid-amine-diluent complex was predicted as (1,1), (2,1), (1,1,1).