• 제목/요약/키워드: Separation Solvent

검색결과 563건 처리시간 0.027초

Preparation of Composite Membranes of Dense PAA-Poly(BMA-co-MMA) IPN Supported on Porous and Crosslinked Poly(BMA-co-MMA) Sublayer and Their Pervaporation Characteristics

  • Kim, Sung-Chul;Lim, Byung-Yun
    • Macromolecular Research
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    • 제11권3호
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    • pp.163-171
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    • 2003
  • For the pervaporation of water-ethanol mixtures, new composite membranes having poly(acrylic acid)-poly (butyl methacrylate-co-methyl methacrylate) interpenetrati ng polymer network [PAA-P(BMA-co-MMA) IPN] skin layer supported on porous and crosslinked poly(BMA-co-MMA) were prepared. The morphology of the sub-layer of the composite membrane prepared in the presence of 60 wt% solvent showed cellular structure, on the other hand that of sublayer prepared in the presence of 70 wt% solvent presented very porous interconnected pore structure with macrovoids. Permeation rates of the composite membranes were largely influenced by the morphology of the sublayer. Separation factors increased with the increase of the degree of crosslinking of the PAA network. It was found that permeation rates could be increased by introducing anionic charges on carboxyl groups of the PAA. The permeation rate changes of the PAA-P(BMA-co-MMA) IPN composite membranes according to the feed compositions showed quite similar pattern with the swelling behavior in water-ethanol mixtures.

Morphology and Tensile Properties of Polyimide/Polyamideimide Composites from Different Polyimide Precursors (Polyimide 전구체에 따른 Polyimide/Ppolyamideimide 복합체의 형태학 및 인장 특성)

  • 김진봉;최윤희;임병탁;박준상
    • Polymer(Korea)
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    • 제25권2호
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    • pp.160-167
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    • 2001
  • The various compositions of polyimide (PI)/polyamideimide (PAI) composites were prepared by heat treatment of the solvent cast PI precursors/PAI blends. The optical micrographs showed that a good compatibility was observed between poly(amic acid) (PAA) and PAI, but in the case of PAME/PAI mixtures, a phase separation apparently occurred due to the absence of ionic and/or H-bonding forces. Regardless of PI precursors, the similar tensile properties were observed. The tensile modulus of the composites were higher than that of the neat polyimide. The X-ray diffraction patterns of the composites showed that the chain rearrangement of PI was increased due to the plasticizing effect of PAI, which has lower glass transition temperature than that of PI, during thermal imidization process.

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A Stable Supported Liquid membrane Composed of Polypropylene Glycol and Tributyl Phosphate for Phenol Separation from Aqueous Solution

  • Ahn, Hyo-Seong;Lee, Yong-Taek;Kim, Myung-Soo
    • Korean Membrane Journal
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    • 제1권1호
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    • pp.81-85
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    • 1999
  • Tributyl phyosphate(TBP) polypropylene glycol 4000(PPG-4000) and the mixture of two compounds were examined as a liquid membrane in a supported liquid membrane (SLM) to separate phenol from aqueous solution.The feed concentration of phenol was varied in a broad range from 500 mg/L to 5000 mg/L and different types of liquid membrane were prepared to elucidate their effects on separation of phenol. It was found that the modified PPG 4000 with TBP and toluene diisocyanate(TDI) might be used as a proper liquid membrane because the mass transfer rate examined with this membrane was higher than that through methyl isobutyl ketone (MIBK) which has been used as a conventional solvent in a solvent extraction process. The breakthrough pressure of the SLM is defined to be the pressure difference across the membrane at which the supported liquid membrane is not kept in the pores any more. it indicates how the SLM is stable., It was found that the breakthrough pressure of the modified PPG-4000 was much higher than those of typical organic solvents.

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A Rapid Method of Ginsenoside Analysis in HPLC by Pretreatment through the reverse-phase minicolumn (역상소형컬럼 전처리를 이용한 Ginsenoside의 신속정량법)

  • Lee, Mee-Kyoung;Lim, Sun-Uk;Park, Hoon
    • Journal of Ginseng Research
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    • 제12권2호
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    • pp.164-172
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    • 1988
  • The solvent separation step in the conventional method for quantitative analysis of ginsenosides was substituted by purification through a small reverse-phase $C_18$-column resulting in the decrease of analysis time by one fourth. New method showed high recovery of total ginsenosides but low recovery in protopanaxatriol-ginsenosides. Sugars did not affect the recovery by the amount in usual root sample. Coefficient of variation in recovery of ginsenosides was lower in the rapid minicolumn method. Optimum load of ginsenosides to minicolumn was 10 to 15 mg. The rapid minicolumn method showed highly significant correlation with the solvent separation method for dried root and red ginseng. For the rapid minicolumn method a small acryl device was used for the simultaneous extraction of 8 samples. This method appeared to be beneficial in cost and for the health of analyst.

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Solvent Extraction of Platinum Group Metals from the leach Liquor of Spent Automotive Catalyst (자동차(自動車) 폐촉매(廢觸媒)의 침출액(浸出液)으로부터 백금족(白金族) 금속(金屬)의 용매추출(溶媒抽出))

  • Kim, Mi-Ae;Lee, Jae-Chun;Kim, Chi-Kwon;Kim, Min-Seuk;Kim, Byung-Su;Yoo, Kyoung-Keun
    • Resources Recycling
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    • 제15권5호
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    • pp.3-10
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    • 2006
  • The solvent extraction for the separation of platinum group metals from the leach liquor of spent automotive catalysts has been studied. Tri-n-butyl phosphate (TBP), tri-n-octylamine (TOA) and di-n-hexyl sulfide (DHS) were used as extractants and kerosene as a diluent. The extraction behavior of platinum, palladium and rhodium has been investigated as functions of different kinds of extractants and their concentrations. In addition, the extraction behavior of the major metal impurities such as cerium, lead, iron, magnesium and aluminum has been investigated. Platinum and palladium were extracted with TBP. And platinum, palladium and rhodium were extracted with TOA. Platinum was co-extracted with palladium into the organic phase by solvent extraction using SFI-6 of DHS extractant, but only palladium was selectively extracted with SFI-6R. The selective extraction of palladium with SFI-6R was found better than that with SFI-6, but the kinetics of extraction with SFI-6R was found poor in comparison to SFI-6. The metal impurities extracted simultaneously during the extraction of platinum group metals should be removed in scrubbing and stripping processes. A suitable process has been proposed for the separation of platinum group metals from the leach liquor of spent automotive catalysts. Initially palladium was extracted with SFI-6R, followed by the separation of platinum with TBP or TOA leaving rhodium in the raffinate.

Effects of Solvent on the Fabrication of Poly(L-lactide) Scaffold Membranes through Phase Inversion (상전이를 통한 Poly(L-lactide) 스캐폴드 막의 제조에서의 용매의 효과)

  • Cho, Yu Song;Kim, Young Kyoung;Koo, Ja-Kyung;Park, Jong Soon
    • Membrane Journal
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    • 제24권2호
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    • pp.113-122
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    • 2014
  • Porous poly(L-lactic acid)(PLLA) scaffold membranes were prepared via. phase separation process. Chloroform, dichloromethane and 1,4-dioxane were used as solvent and, ethyl alcohol was used as non-solvent. Morphologies, mechanical properties and mass transfer characteristics of the scaffold membranes were investigated through SEM, stress-strain test and glucose diffusion test. The scaffold membranes obtained from the casting solutions with chloroform and with dichloromethane showed similar morphologies. They showed sponge-like porous structure with the pore size in the range of $3-10{\mu}m$ and, their porosities were in 50-80% range. Using 1,4-dioxane as solvent, nano-fibrous scaffold membranes with porosities over 80% were fabricated. When the polymer content in the solution with 1,4-dioxane was lowered to 4%, highly porous, macroporous and nano-fibrous scaffold membranes were obtained. The size of the macropore was tens of the microns and the porosity was around 90%. These results indicate that the solvent has significant effect on the scaffold membrane structure and, that scaffold membranes with various structures can be fabricated through phase separation method by choosing solvent and by controlling polymer concentration in the casting solution.

The Microwave-Assisted Extraction of Fats from Irradiated Meat Products for the Detection of Radiation-Induced Hydrocarbons

  • Kwon, Joong-Ho;Kausar, Tusneem;Lee, Jeong-Eun;Kim, Hyun-Ku;Ahn, Dong-U
    • Food Science and Biotechnology
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    • 제16권1호
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    • pp.150-153
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    • 2007
  • Hydrocarbons have been successfully used as a chemical marker in order to identify irradiated from non-irradiated foods. The method for determining hydrocarbons consists of extraction of fats, followed by separation of hydrocarbons by florisil column chromatography, and then identification of hydrocarbons by GC/MS. Currently, solvent extraction method for fats has certain limitations with regard to extraction time and solvent consumption. Commercial hams and sausage were irradiated at 0 and 5 kGy, and the efficiency of microwave-assisted extraction (MAE) and conventional solvent extraction (CSE) methods on the extraction of radiation-induced hydrocarbons from the meat products was compared. Significant levels of hydrocarbons, mainly composed of 1,7-hexadecadien, 1,7,10-hexadecatriene, and 6,9-heptadecadiene, were detected in the extracts from irradiated hams and sausages by both CSE and MAE methods. Both methods were acceptable in extracting hydrocarbons from samples, but MAE method required apparently reduced amounts of solvent from 150 (CSE) to 50 mL and reduced extraction time from 23 (CSE) to 5 min.

Ionic Liquid as a Solvent and the Long-Term Separation Performance in a Polymer/Silver Salt Complex Membrane

  • Kang, Sang-Wook;Char, Kook-Heon;Kim, Jong-Hak;Kang, Yong-Soo
    • Macromolecular Research
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    • 제15권2호
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    • pp.167-172
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    • 2007
  • The reduction behavior of silver ions to silver nanoparticles is an important topic in polymer/silver salt complex membranes to facilitate olefin transport, as this has a significant effect on the long-term performance stability of the membrane. In this study, the effects ofthe solvent type on the formation of silver nanoparticles, as well as the long-term membrane performance of a solid polymer/silver salt complex membrane were investigated. These effects were assessed for solid complexes of poly(N-vinyl pyrrolidone) $(PVP)/AgBF_4$, using either an ionic liquid (IL), acetonitrile (ACN) or water as the solvent for the membrane preparation. The membrane performance test showed that long-term stability was strongly dependent on the solvent type, which increased in the following order: IL > ACN >> water. The formation of silver nanoparticles was more favorable with the solvent type in the reverse order, as supported by UV-visible spectroscopy. The poor stability of the $(PVP)/AgBF_4$ membrane when water was used as the solvent might have been due to the small amount of water present in the silver-polymer complex membranes actively participating in the reduction reaction of the silver ions into silver nanoparticles. Conversely, the higher stability of the $(PVP)/AgBF_4$, membrane when an IL was used as the solvent was attributable to the cooperative coordination of silver ions with the IL, as well as with the polymer matrix, as confirmed by FTIR spectroscopy.

Mutual Separation of Am(III) and Eu(III) by Solvent Extraction with Cyanex 301 (Cyanex 301에 의한 Am(III)과 Eu(III)의 상호분리)

  • Yang, Han-Beom;Lim, Jae-Gwan;Lee, Eil-Hee;Yoo, Jae-Hyung
    • Applied Chemistry for Engineering
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    • 제10권1호
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    • pp.143-147
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    • 1999
  • The present paper describes the solvent extraction behaviors and the mutual separation of Am and Eu by sulphur bearing Cyanex 301 acidic extractant in sodium nitrate solutions. Original Cyanex 301 was not able to separate the Am and Eu because of their similar extraction behaviors. The saponification of commercial Cyanex 301 was performed by small amounts of 8 M NaOH solutions and saponified Cyanex 301 was able to separate of Am from Eu with high selectivity in sodium nitrate aqueous solution. The separation factors ($SF_{Am/Eu}$) were increased with saponified ratio of commercial Cyanex 301, pH of sodium nitrate solution and initial concentration of Eu. To obtain the homogeneous saponified Cyanex 301, heterogeneous saponified Cyanex 301 was treated with addition of octyl alcohol or filtration. The observed $SF_{Am/Eu}$ was 32.3 for the former and 930 for the latter. Finally, the stripping behaviors of Am and Eu were similar and stripping yields showed 96.1% for the 1 M $NaNO_3$(pH=1.3) and 99% for the mixture solution of 0.05 M DTPA and 1.5 M lactic acid.

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Controlling the Morphology of Polyvinylidene-co-hexafluoropropylene (PVDF-co-HFP) Membranes Via Phase Inversion Method (상전이법을 이용한 P(VDF-co-HFP) 분리막 구조제어)

  • Song, Ye Jin;Kim, Jong Hoo;Kim, Ye Som;Kim, Sang Deuk;Cho, Young Hoon;Park, Ho Sik;Nam, Seung Eun;Park, You In;Son, Eun Ho;Kim, Jeong F.
    • Membrane Journal
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    • 제28권3호
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    • pp.187-195
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    • 2018
  • In this work, the morphology of polyvinylidene-co-hexafluoropropylene (PVDF-co-HFP) membranes were systemically investigated using phase inversion technique, to target membrane contactor applications. As the presence of macrovoids degrade the mechanical integrity of the membranes and jeopardize the long-term stability of membrane contactor processes (e.g. wetting), a wide range of dope compositions and casting conditions was studied to eliminate the undesired macrovoids. The type of solvent had significant effect on the membrane morphology, and the observed morphology were correlated to the physical properties of the solvent and solvent-polymer interactions. In addition, to fabricate macrovoid-free structure, the effects of different coagulation temperatures, inclusion of additives, and addition of nonsolvents were investigated. Due to the slow crystallization rate of P(VDF-co-HFP) polymer, it was found that obtaining porous membrane without macrovoids is difficult using only nonsolvent-induced phase separation method (NIPS). However, combined other phase inversion methods such as evaporation-induced phase separation (EIPS) and vapor-induced phase separation (VIPS), the desired membrane morphology can be obtained without any macrovoids.