• Proceedings of the Membrane Society of Korea Conference
• /
• 2008.05a
• /
• pp.271-272
• /
• 2008

• Membrane Journal
• /
• v.9 no.1
• /
• pp.43-50
• /
• 1999

The effects of water vapor on the permeation rates of oxygen and nitrogen through poly sulfone hollow-fiber membrane were investigated. The permeation rates of both 02 and $O_2$ were decreased significantly owing to the presence of water vapor. The permeation rate of oxygen with 100% relative humidity was reduced by as much as 20%, while the permeation rate of nitrogen decreased by 14% at 30 "C and 3kgf/$cm^2$ of upstream pressure. The permeation rates of $O_2$ were declined monotonously with running time and arrived at steady state values by the presence of water vapor. However, those of $N_2$ increased tentatively and then decreased to the steady state.tate.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1998.04a
• /
• pp.97-98
• /
• 1998

1. Introduction : Polypropylene(PP) membrane is widely used in the field of microfiltration and ultrafiltration. However, the hydrophobicity of PP causes the adsorption of hydrophobic and amphoteric solutes in the feed. Surface modification techniques of membrane through the treatment of hydrophilizing agents, coating of hydrophilic compounds, UV, plasma and high energy irradiation, etc. can have a great effect on propensities to prevent the protein from staining membranes. Among them, the modification to hydophilize membrane surface using UV is very simple and effective. Recently many studies for more effective surface modification have been conducted. Iwata et al. prepared membranes by grafting polyethylene glycol diacrylate macromer(PEGDA) onto polysulfone with plasma using a glow discharge reactor which prevent the oil from staining the membrane. The primary mechanism contributing to the membranes is preventing the oil from directly contacting the surface of the membrane as the PEGDA chains dissolved into emulsion. To evaluate their feasibility for use as a anti-fouling separation membrane, we prepared hydrophilic membranes by UV irradiation method and investigated their characteristics.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1995.04a
• /
• pp.11-15
• /
• 1995

Polysulfone (PS) membranes were prepared by the phase inversion process using water or isopropanol as nonsolvent. The Flory-Huggins theory for a ternary system nonsolvent/solvent/polymer is applied to describe the thermodynamic equilibria of the components. The calculated ternary phase equilibria show that demixing of a PS binary solution with n-methylpyrrolidone (NMP) will be fast in a water coagulation bath and will be delayed in an isopropanol bath. The prepared membranes were characterized by SEM, gas adsorption-desorption measurement, and permeability test. The membrane, which is precipitated by fast demixing in a water bath, has nodular structures in the skin region and includes finger-like cavities in the sublayer. The membrane coagulated by isopropanol has a very dense and thick skin structure, which is formed by delayed demixing. The membrane coagulated by isopropanol showed considerably lower pore volume and surface area compared to that observed with water coagulation method. With dimethylformamide (DMF) as solvent and 2-3 wt% of water, the solution can show the liquid-liquid phase separation due to agglomation of the polymer-lean phase from the homogeneous solution. The membranes, which were coagulated near an equilibrium state, show the large (micron size) round pores in the whole membranes. The pores do not contribute the permeation characteristics.

• Bulletin of the Korean Chemical Society
• /
• v.24 no.9
• /
• pp.1333-1338
• /
• 2003

Hollow Fiber flow field-flow fractionation (HF-FlFFF) has been tested in polyacrylonitrile (PAN) membrane channel in order to compare it with polysulfone (PSf) membrane channel. It has been experimentally shown that the separation time of 0.05-0.304 ${mu}m$ polystyrene latex (PSL) standards in PAN membrane channel is shorter than that in PSf channel by approximately 65%. The optimized separation condition in PAN membrane is ${\dot V}_{out}/{\dot V}_{rad}=1.4/0.12\;mL/min$, which is equal to the condition in PSf membrane channel. In addition both the resolution ($R_s$) and plate height (H) in PAN membrane channel are better than that in PSf membrane channel. The membrane radius was obtained by back calculation with retention time. It shows that the PSf membrane is expanded by swelling and pressure, but the PAN membrane doesn't expand by swelling and pressure.

• Membrane Journal
• /
• v.6 no.1
• /
• pp.37-43
• /
• 1996

Chitosan composite membranes were prepared by casting chitosan solution onto porous polysulfone ultrafiltration membrane. Composite membranes to separate water from aq. ethanol solution were chemically crosslinked by using various crosslinking agent, glyoxal, terephthalaldehyde and glutaraldehyde. The morphology of surface crosslinked chitosan composite membranes were examined by scanning electron microscopy. ATR-FTIR was employed to confirm the crosslinking mechanism of surface crosslinked chitosan composite membranes. In the case of glutaraldehyde, optimum separation factor and decreasing trend of flux were shown.

• Journal of the Korean institute of surface engineering
• /
• v.41 no.3
• /
• pp.102-108
• /
• 2008

In this paper, the LiF and polymer thin film as passivation layer have been evaporated on green OLED devices. HDPE, polyacenaphthylene, polytetrafluoroethylene, poly(2,6-dimethyl-1,4-pheneylene oxide), poly sulfone and poly(dimer-acid-co-alkyl poly-amine) have been used as polymer materials. The optical transmittance of evaporated polymer thin film was very good as an above 90% in visible range. The morphology of polymer thin film was measured by AFM. As a result of the measurement average roughness($R_a$) value of the polysulfone was very low as 2.2 nm. The green OLED devices with a structure of ITO/HIL/HTL/EML/Buffer/Al in series of various passivation films were fabricated and analyzed. It was observed that an OLED device with LiF as first passivation film has shown the good electrical and optical property, and all kind of polymer films did not influence on the I-V-L characteristics and the life time of OLED devices. Therefore, we found that polymer layer played a key role as a buffer layer between the inorganic passivation layers to relieve the stress of the inorganic layers.

• Membrane Journal
• /
• v.7 no.4
• /
• pp.191-198
• /
• 1997

Membrane formation mechanism by the phase inversion has been investigated in order to control the membrane morphology. It was found that finger-like structures were obtained when the heat of mixing between the solvent and non-solvent is exothermic, while sponge-like structures were obtained when they are endothermic in polystyrenes as well as in polyimides (Torlon and polyimide made frorn 3,3'4,4'-benzophenontetracarboxylic diahmydride and 1,4-phenylene diarnine) membranes. This concept was applied to control the morphology of polysulfone membranes simply by adding a solvent additive by adjusting the heat of mixing. A crude, but simple, relationship between the heat of mixing and the exchange rate of the solvent with non-solvent has been also developed.

• Membrane and Water Treatment
• /
• v.8 no.4
• /
• pp.323-336
• /
• 2017

The main challenge in many applications of acetic acid is acid dehydration and its recovery from wastewater streams. Therefore, the performance of polyamide thin film composite is evaluated to separate acetic acid from water. To reach this goal, the formation of polyamide layer on polysulfone support membrane was investigated via interfacial polymerization (IP) of meta-phenylenediamine (MPD) in water with trimesoyl chloride (TMC) in hexane. Also, the effect of synthesis conditions, such as concentration of monomers and curing temperature on separation of acetic acid from water were investigated by reverse osmosis process. Moreover, the separation mechanism was discussed. The solute permeation was carried out under applied pressure of 5 bar at $25^{\circ}C$. Surface properties of TFC membrane were characterized by ATR-FTIR, SEM and AFM. The performance test indicated that 3.5 wt% of MPD, 0.35 wt% of TMC and curing temperature of $75^{\circ}C$ are the optimum conditions. Moreover, the permeate flux was $4.3{\frac{L}{m^2\;h}}$ and acetic acid rejection was about 43% at these conditions.

• Membrane and Water Treatment
• /
• v.6 no.4
• /
• pp.309-321
• /
• 2015

We report in this study the synthesis of mixed matrix reverse osmosis membranes by interfacial polymerization (IP) of thin film nanocomposite (TFNC) on porous polysulfone supports (PS). This paper investigates the synthesis of ZnO nanoparticles (NPs) using the sol-gel processing technique and evaluates the performance of mixed matrix membranes reached by these aerogel NPs. Aqueous m-phenyl diamine (MPD) and organic trimesoyl chloride (TMC)-NPs mixture solutions were used in the IP process. The reaction of MPD and TMC at the interface of PS substrates resulted in the formation of the thin film composite (TFC). NPs of ZnO with a size of about 25 nm were used for the fabrication of the TFNC membranes. These membranes were characterized and evaluated in comparison with neat TFC ones. Their performances were evaluated based on the water permeability and salt rejection. Experimental results indicated that the NPs improved membrane performance under optimal concentration of NPs. By changing the content of the filler, better hydrophilicity was obtained; the contact angle was decreased from $74^{\circ}$ to $32^{\circ}$. Also, the permeate water flux was increased from 26 to 49 L/m2.h when the content of NPs is 0.1 (wt.%) with the maintaining of lower salt passage of 1%.