• Membrane Journal
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• v.34 no.5
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• pp.225-233
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• 2024

Membrane technology has been used in separation processes such as wastewater treatment, desalination, and hemolysis. However, in proccess of the non-solvent-induced phase separation (NIPS) which is the most widely adopted method for fabricating porous polymer membranes, using toxic organic solvents is a critical problem for environmental aspect. To resolve this problem, the aqueous phase separation (APS) has received attention, which produces polymeric membranes without using the organic solvent. In this review, we provide principle and process of APS. The ratio of monomers, pH and salt concentration in aqueous solution, viscosity of casting solutions, and concentration of cross-linkers can leverage the structures of membranes.

• KSBB Journal
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• v.15 no.6
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• pp.556-559
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• 2000

Cyclodextrin Glucanotransferase(EC 2.4.1.19 : 1,4-${\alpha}$-glucano) transferase, cyclizing; CGTase) can be separated and recovered in an aqueous two-phase system composed of poly(ethylene glycol)(PEG)/dextran and PEG/salt. In an aqueous two-phase system consisting of PEG 35000 (5%) and dextran T2000 (7%), all cell and debris were collected at the interphase. CGTase partitioned to the denser dextran phase at an yield of 83.4%. On the other hand, in an aqueous two-phase system consisting of PEG 35000 (10%) and sodium phosphate (15%), CGTase partitioned to the denser salt phase at an yield of 95.5%. In order to recover CGTase using an aqueous two-phase system, the PEG/salt system proved to be more efficient than the PEG/dextran system in terms of yield and cost.

• Journal of Institute of Convergence Technology
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• v.4 no.2
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• pp.23-26
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• 2014

As an effective separation method for biomolecules, aqueous two-phase systems based on ionic liquids were suggested. Hydrophobic ionic liquids are more expensive and viscous in spite of their usage in the ionic liquid/water biphasic extraction compared with hydrophilic ionic liquids. In case of aqueous two-phase systems using hydrophilic ionic liquids, they can be diluted in aqueous phase. Experimental results show that aqueous two phase systems can be formed by adding appropriate amount of ionic liquids to aqueous salts solutions. The viscosity of ionic liquid aqueous phase is proportional to the cation chain length in ionic liquids. It is founded that the ionic liquid based aqueous two phase systems are effective for the separation of biomolecules such as acrylic acid.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.244-249
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• 2007

Fluidic conditions for the separation of phases were surveyed in a microfluidic aqueous two-phase extraction system. The infusion ratio between polyethylene glycol (PEG) and dextran solution defines the concentrations of each polymer in micro-channel, which determine the phase-separation. The appropriate ratio between PEG (M.W. 8000, 10%, w/v) and dextran T500 (M.W. 500000, 5%, w/v) in order to perform the separation of phases of both polymers was observed as changing the mixed ratio of both polymers. Based on the fluidic conditions, stable two-phase solutions were obtained within 4% to 8% and 3% to 1% of PEG and dextran, respectively. In addition, the characteristics of the two-phase were discussed. The separation technique studied in the paper can be applied for the implementation of a lab-on-a chip which can detect various biological entities such cells, bacterium, and virus in an integrated manner using built in a biosensor inside the chip.

• Nuclear Engineering and Technology
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• v.51 no.3
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• pp.761-768
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• 2019

Understanding the phenomena of formation of single drops is necessary to understand the hydrodynamics in solvent extraction equipment which are used for separation of nuclear materials. In this work, the phenomena of aqueous phase and organic phase drop formation at submerged nozzles are compared by conducting experiments with 30%TBP (v/v) in dodecane as the organic phase and nitric acid as the aqueous phase. Two different nozzles and three different nitric acid concentrations are used. For each nozzle and nitric acid concentration, velocity of the dispersed phase is varied. Drops of aqueous phase formed at downward oriented nozzles submerged in organic phase are observed to be smaller than the drops of organic phase formed at upward oriented nozzles submerged in aqueous phase. Correlations to estimate drop diameter are proposed.

• Journal of Industrial Technology
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• v.19
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• pp.189-195
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• 1999

A study on the separation Cu, Ni, and Co was carried out using LIX 84 leachate, chelate extractant. For this test, artificial test solution was prepared by varing concentrations of Cu, Ni, Co, $(NH_4)_2CO_3$ and $(NH_4)_2SO_4$. It found that pH of the solution was very important factor for the separation of nickel from copper. The results showed that nickel was effectively extracted from copper by using LIX 84 at pH 1.0 to 1.2. The volume ration or organic to aqueous phases was 1.0. According to the McCabe-Thiele diagram, the extraction rate of copper was 99 percents at the equal ratio of organic to aqueous phase in three stages.

• Food Science and Biotechnology
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• v.14 no.1
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• pp.131-136
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• 2005

The selective extraction behavior of lactoferrin (Lf) from whey protein mixture was examined using reverse micelles formed by the cationic surfactant, cetyldimethylammonium bromide (CDAB). The major whey proteins, including ${\beta}$-lactoglobulin, ${\alpha}$-lactalbumin and bovine serum albumin, were solubilized from aqueous phase to organic phase while Lf was recovered in the aqueous phase. The solubilization behaviors of the proteins were manipulated by the process parameters such as the pH and salt concentration of the aqueous phase and the surfactant concentration in the organic phase. Efficient forward extraction was achieved with sodium borate buffer (50 mM, pH 9) containing 50 mM KCl and organic phase containing 100 mM CDAB. Based on SDS-PAGE and densitometry, about 96% of the initial Lf remained in the aqueous phase after forward extraction. The dialyzed Lf fully maintained its bacteriostatic activity against E. coli O157:H7.

• Food Science of Animal Resources
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• v.24 no.1
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• pp.80-85
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• 2004

This study was carried out to separate immunoglobulin G(IgG) from colostrum using reverse micellar extraction of cationic surfactant and to suggest suitable extraction conditions. The reconstituted colostrum powder was solubilized into a reverse micellar phase containing CDAB(cetyldimethylethyl ammonium bromide) by mixing equal volume of the aqueous and organic phase with constant stirring. The solubilization of proteins from the aqueous to the organic phase was manipulated by pH and ionic strength of the aqueous phase and concentration of surfactant in the organic phase. Based on the SDS-PAGE and densitometry, about more than 90% of initial IgG was remained in the aqueous phase after reverse micellar extraction. Although the aqueous phase contained lactoferrin and bovine serum albumin as minor components, about 93% of the total protein was IgG. The efficient extraction was achieved by the reaction of sodium phosphate buffer(pH 8) containing 50 mM KCl and organic phase containing 100 mM CDAB. The separation of IgG using reverse micellar extraction was simple, highly efficient and easy to be scaled up.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.2978-2982
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• 2013

A doubly tethered $N-CH_3$ amide chiral stationary phase (CSP 4) based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid was applied to the resolution of an antiarrythmic agent, tocainide, and its analogues and the chromatographic resolution results were compared with those on a singly tethered N-H amide CSP (CSP 1), a singly tethered $N-CH_3$ amide CSP (CSP 2) and a doubly tethered N-H amide CSP (CSP 3) under an identical aqueous mobile phase condition. CSP 4 was found to be generally better than other CSPs in terms of the separation factors (${\alpha}$) and resolutions (RS). The retention times of analytes denoted by the retention factors ($k_1$) on CSP 4 were quite long compared to those on other CSPs because of the improved lipophilicity of CSP 4. The long retention times of analytes on CSP 4 were successfully controlled by the addition of a small amount of ammonium acetate to aqueous mobile phase without hurting the chiral recognition efficiency. The variation of the content and type of organic and acidic modifier in aqueous mobile phase was found not to change the chiral recognition efficiency significantly.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.504-507
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• 2002

A separation/purification process for enzymatic sugar ester production was investigated The crude reaction mixture contained sugar ester and unreacted fatty acid in acetone. The reaction mixture was mixed with KOH/phosphate buffer. Hexane was then added to enhance phase separation. Three phases formed: a lower aqueous phase containing nothing of interest, a polar organic solvent middle phase that contained mostly fatty acid soaps, and a hexane-rich upper phase that contained mostly sugar ester. Distribution coefficient of each component was measured.