• Macromolecular Research
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• 제16권7호
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• pp.590-595
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• 2008

The pressure driven membrane process has been a breakthrough in the removal of pollutants from drinking water. These experiments examined the removal of chlorophenol compounds from water using low pressure membranes. The removal performance of the membranes was based primarily on size exclusion. Apart from size exclusion, the polarity and pKa of the compounds also influences the membrane performance. The molecular size and dipole moments of the respective molecules were calculated using a quantum chemical method. The rejection of pollutants also followed the same trend as salt rejection by the membranes.

• Macromolecular Research
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• 제11권1호
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• pp.53-61
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• 2003

A molecular-thermodynamic model is developed for the salt-induced protein precipitation. The protein molecules interact through four intermolecular potentials. An equation of state is derived based on the statistical mechanical perturbation theory with the modified Chiew's equation for the fluid phase, Young's equation for the solid phase as the reference system and a perturbation based on the protein-protein effective two body potential. The equation of state provides an expression for the chemical potential of the protein. In a single protein system, the phase separation is represented by fluid-fluid equilibria. The precipitation behaviors are simulated with the partition coefficient at various salt concentrations and degree of pre-aggregation effect for the protein particles. In a binary protein system, we regard the system as a fluid-solid phase equilibrium. At equilibrium, we compute the reduced osmotic pressure-composition diagram in the diverse protein size difference and salt concentrations.

• 멤브레인
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• 제31권1호
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• pp.61-66
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• 2021

본 연구는 현재 올레핀/파라핀 분리에서 사용되는 극저온 분리법을 대체하기 위한 촉진수송 분리막에 대한 연구이다. 촉진수송 분리 막을 상업화하기 위해서는 비용 절감 또한 매우 중요한 요소이다. 하지만 많은 연구가 이루어지고 있는 AgBF4는 상대적으로 고가인 은 염이기 때문에 이를 대체하기 위해 비교적 저렴한 AgCF3SO3를 이용하여 PEBAX-2533/AgCF3SO3/Al(NO3)3 복합막을 제조하였다. 분리막의 특성은 SEM, FT-IR, RAMAN을 통해 분석되었으며, 이번 연구를 통해 고분자 매트릭스가 장기 안정성에 영향을 준다는 사실을 확인하였다.

• Advances in materials Research
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• 제2권1호
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• pp.51-64
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• 2013

Enantioselective macromer of trimesic acid was prepared using S(-) menthol with trimesoyl chloride on polyimide (PI) ultrafiltration membrane. The chemical composition of macromer as well as polyimide ultrafiltration membrane was determined by ATR-FTIR Spectroscopy. The optical resolution of chiral alcohols was performed in pressure driven process. The effect of monomer solutions concentration, effect of air-drying time of S(-) menthol solution, effect of reaction time, effect of operating pressure, effect of feed concentration of racemate on the performance of macromer was studied. The synthesised material exhibits separation of chiral alcohols (menthol ~23% and sobrelol ~21%).

• 한국물환경학회지
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• 제36권1호
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• pp.48-54
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• 2020

This paper presents a screening protocol for the selection of solvents available for the solvent extraction desalination process. The desalination solvents hypothetically and theoretically require the capability of (1) Forming hydrogen bonds with water, (2) Absorbing some water molecules into its non-polar solvent layer, (3) Changing solubility for water-solvent separation, and (4) Rejecting salt ions during absorption. Similar to carboxylic acids, amine solvents are solvent chemicals applicable for desalination. The key parameter for selecting the potential solvent was the octanol-water partitioning coefficient (Kow) of which preferable value for desalination was in the range of 1-3. Six of the 30 amine solvents can absorb water and have a variable, i.e., temperature swing solubility with water molecule for water-solvent separation. Also, the hydrogen bonding interaction between solvent and water must be stronger than the ion-dipole interaction between water and salt, which means that the salt ions must be broken from the water and only water molecules absorbed for the desalination. In the final step, three solvents were selected as desalination solvents to remove salt ions and recover water. The water recovery of these three solvents were 15.4 %, 2.8 %, 10.5 %, and salt rejection were 76 %, 98 %, 95 %, respectively. This study suggests a new screening protocol comprising the theoretical and experimental approaches for the selection of solvents for the desalination method which is a new and challenges the desalination process in the future.

• Membrane and Water Treatment
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• 제7권6호
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• pp.477-493
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• 2016

Immediate use of activated carbon incorporated polysulfone membrane application for dye separation was reported in this work. Dimethylformamide (DMF) was used as the solvent for the membrane preparation. The membrane thus prepared were characterized in terms of surface morphology, ATR-FTIR, AFM, experimental results as membrane performance. The resultant nanofiltration (NF) membranes were tested with Congo red dye concentration 200 mg/L. The water permeability was found to be considerably higher than that reported in literature. Experimental results show that the real rejection of the Congo red is 99.57% over the transmembrane pressure 100 psi using 30% activated carbon incorporated membrane. Prepared NF membranes shows the corresponding permeates fluxes were $40Lm^{-2}h^{-1}$ to $82Lm^{-2}h^{-1}$ with different activated carbon percentage incorporated in polysulfone membrane. The present study demonstrated that dye rejection enhanced NF may be a feasible method for the dye wastewater treatment. The overall observations thus indicated that toxic residual dyes can be appreciably separated from the membrane technology, provided that the accompanying polymeric membrane, activated carbon as binding agents and the process parameter levels are astutely selected.

• 대한화학회지
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• 제34권1호
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• pp.69-75
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• 1990

모자나이트 광물 중에 포함된 각각 희토류 원소를 이온회합 크로마토그래피 방법으로 분리 및 정량하였다. 정량하기 전에 양이온교환수지(Dowex 5OW-X8) 칼럼으로 희토류 원소를 집단 분리하였다. 이 때 수지 칼럼에 의하여 희토류 원소가 정량적으로 회수되며, 시료 중의 공존이온으로부터 깨끗이 분리됨을 방사성 추적자 및 유도쌍 결합 분광-질량분석법(ICP-MS)으로 각각 확인 하였다. 역상 칼럼($\mu$-Bondapak $C_{18}$)에 의하여 미량(ppm)의 희토류 원소를 pH 4.6의 $\alpha$-hydroxyisobutyric acid으로 0.05M부터 0.3M까지 기울기 용출하여 각각 분리하였다. 희토류 원소와 PAR (4-(2-pyridylazo)-resorcinol monosodium salt)과의 포스터 칼럼 착색반응을 통하여 각각의 희토류 원소를 검출하였다.

• 멤브레인
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• 제13권2호
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• pp.125-129
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• 2003

은염이 함유된 고분자 전해질을 이용한 올리핀 촉진수송 분리막은 고체상에서 높은 올레핀/파라핀 분리 성능을 나타내었다 본 연구에서는, 프로필렌/프로판 분리 선택도와 투과도의 성능을 향상시키기 위해 아미노산의 일종인 valine을 고분자 전해질막에 첨가하였다. FT-lR 분광학을 통해 valine의 양이온과 은염의 음이온이 상호작용을 하고, 그 결과 valine은 은이온의 활성도를 증가시킴을 알 수 있었다. 따라서 valine을 포함하고 있는 촉진수송 분리막은 valine이 없을 때보다 더 높은 선택도와 투과도를 나타내었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 추계학술발표대회
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• pp.12.2-12.2
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• 2009

The work describes anoptimized process to highly efficient and convenient preparation in highthroughput magnetic human DNA separation with chemically functionalizedsilica-coated magnetic nanoparticles. The effect of nanoparticle's size and the surface's hydrophilicity change were studied for magnetic DNA separation process, inwhich the optimum efficiency was explored via the function of the amino-groupnumbers, particle size, the amount of the nanoparticles used, and theconcentration of NaCl salt. The DNA adsorption yields were high in terms of theamount of triamino-functionalized nanoparticles used, and the average particlesize was 25 nm. The adsorption efficiency of aminofunctionalized nanoparticleswas the 4-5 times (80-100%) higher compared to silica-coated nanoparticles only(10-20%). DNA desorption efficiency showed an optimum level of over 0.7 M ofthe NaCl concentration. To elucidate the agglomeration of nanoparticles afterelectrostatic interaction, the Guinier plots were calculated from small angleX-ray diffractions in a comparison of the results of electron diffraction TEM,and confocal laser scanning microscopy. Additionally, the direct separation ofhuman genomic DNA was achieved from human saliva and whole blood with highefficiency.

• Nuclear Engineering and Technology
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• 제46권3호
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• pp.395-406
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• 2014

This study provides a fundamental understanding of a cold finger melt crystallization technique by exploring the heat and mass transfer processes of cold finger separation. A series of experiments were performed using a simplified LiCl-CsCl system by varying initial CsCl concentrations (1, 3, 5, and 7.5 wt%), cold finger cooling rates (7.4, 9.8, 12.3, and 14.9 L/min), and separation times (5, 10, 15, and 30 min). Results showed a potential recycling rate of 0.36 g/min with a purity of 0.33 wt% CsCl in LiCl. A CsCl concentrated drip formation was found to decrease crystal purity especially for smaller crystal formations. Dimensionless heat and mass transfer correlations showed that separation production is primarily influenced by convective transfer controlled by cooling gas flow rate, where correlations are more accurate for slower cooling gas flow rates.