• Title/Summary/Keyword: Asymmetric Membrane

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Preparation of Hydroxy Polyimde Membranes for Gas Separation by Phase Inversion Method (상전이법을 이용한 기체 분리용 Hydroxy Polyimide 막의 제조)

  • Woo, Seung-Moon;Choi, Jong-Jin;Nam, Sang-Yong
    • Membrane Journal
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    • v.22 no.1
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    • pp.62-71
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    • 2012
  • In this study, for preparation of gas separation membrane with high permeability, hydroxy polyimide was synthesized using 6FDA and APAF. Synthesis of HPI was confirmed by H-NMR and FT-IR, thermal property of membrane was characterized by Differential scanning calorimetric (DSC) and thermogravimetric analyzer (TGA). Especially, the synthesized HPI can possible to search conversion to PBO at $450^{\circ}C$. To obtain the membrane having high permeability, ternary system consist of polymer, solvent and non-solvent additive was introduced, asymmetric HPI flat sheet membrane was prepared by phase inversion method. Finally, the change of morphology with each component was observed through FE-SEM.

Coagulant bath medium effect towards polylactic acid membranes structure and methylene blue dye removal

  • Amira M. Nasib;Stephen Simon;Syahmie M. Rasidi;Siti Kartini E. Ab. Rahim;Hoo Peng Yong;Ng Qi Hwa;Khairiraihanna Johari
    • Advances in materials Research
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    • v.13 no.3
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    • pp.243-251
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    • 2024
  • The asymmetric polylactic acid (PLA) membrane was prepared via phase inversion method using non-solvent induced separation (NIPS) technique. This study aims to synthesized as well as to characterize the PLA membrane and evaluating the membrane performance on water flux and permeability. In addition, this research also studied the removal performance of methylene blue dye. The polymer solution has been prepared using 12 wt.% of PLA and dissolved in 88 wt.% of Dimethylacetamide (DMAc) as a solvent. Then, the cast film was immersed in different ratio of coagulant bath medium (distilled water: methanol: ethanol) ranging from 100:0:0, 75:25:0, 75:0:25 and 75:12.5:12.5, respectively). Several characterizations were performed which include, membrane contact angle and membrane porosity. Performance PLA membranes were determined in terms of water flux and permeability at 1 bar transmembrane pressure using dead-end permeation cell. Finally, methylene blue (MB) removal efficiency was tested at the same transmembrane pressure. The findings revealed that the increase of alcohol concentration in coagulant bath resulted in higher porosity and lower contact angle. In short, MB dye rejection efficiency is also closely related to the amount of alcohol ratio used in coagulant baths. Increases in concentration of methanol and ethanol in coagulant bath medium increases the membrane porosity thus increased in efficiency of methylene blue rejection.

Preparation of Asymmetric PES Hollow Fiber Gas Separation Membranes and Their $CO_2/CH_4$ Separation Properties (비대칭구조의 폴리이서설폰 기체분리용 중공사막의 제조 및 이를 이용한 $CO_2/CH_4$ 분리특성)

  • Park, Sung-Ryul;Ahn, Hyo-Seong;Kim, Jeong-Hoon
    • Membrane Journal
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    • v.21 no.4
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    • pp.367-376
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    • 2011
  • Huge amount of $CH_4$ mixtures has been emitted from landfills and organic wastes via anaerobic digestion. The recovery of high purity $CH_4$ from these gases has two merits: reduction of green house gases and production of renewable fuels. Membrane technology based on polymeric materials can be used in this application. In this study, asymmetric gas separation hollow fiber membranes were fabricated to develop the membrane-based bio-gas purification process. Polyethersulfone (PES) was chosen as a polymer materials because of high $CO_2$ permeability of 3.4 barrer and $CO_2/CH_4$ selectivity of 50[1]. Acetone was used as a non-solvent additive because of its unique swelling power for PES and highly volatile character. The prepared PES hollow fiber showed excellent separation properties: 36 GPU of $CO_2$ permeance and 46 of $CO_2/CH_4$ selectivity at optimized preparation conditions: 9wt% acetone content, 10cm air-gap and 4wt% PDMS coating processes. With the PES hollow fiber membranes developed, mixed $CO_2/CH_4$ test was done by changing various operating conditions such as pressures and feed compositions to meet the highest recovery of CH4 with 95% purity. High $CH_4$ recovery of 58 wt% was observed at 10 atm feed pressure for the 50 vol% of $CO_2$ in $CO_2/CH_4$ mixture.

Auditory Model Design for Objective Audio Quality Measurement

  • Dongil Seo;Park, Se-Hyoung;Ryu, Seung-wan;Jaeho Shin
    • Proceedings of the IEEK Conference
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    • 2002.07c
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    • pp.1717-1720
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    • 2002
  • Objective quality measurement schemes that in- corporate properties of the human auditory system. The basilar membrane(BM) acts as a spectrum analyzer, spatially decomposing the signal into frequency components. Each filterbank is an implementation of the ERB, gam-machirp function. This filterbank is level-dependent asymmetric compensation filters. And for the validation of the auditory model, we calculate the CPD. Quality measurement is obtained from the result.

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Performance of Anion Charged Copoly(1,2,4-benzenetricarboxylate/bis[4-(3-aminophenoxy)phenyl]sulfone/3,3',4,4'-benzophenone tetracar boxylate/1,2,3,4-butanetetracerboxylate) Ultrafiltration Membranes (음이온성 Copoly(1,2,4-benzenetricarboxylate/bis[4-(3-aminophenoxy)phenyl]sulfone/3,3',4,4'-benzophenonetetracarboxylate/1,2,3,4-butanetetracerboxylate) 한외여과막의 투과특성)

  • Jeon, Jong-young
    • Journal of the Korean Society of Industry Convergence
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    • v.12 no.4
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    • pp.193-202
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    • 2009
  • In the preparation of anion charged asymmetric ultrafiltration membranes by the conventional phase inversion method, several variables could be adjusted to control membrane permeations. The anion charged materials and its original polymer have good solubility in N-methyl-2-pyrrolidone. The membranes having a hydrophilic property were less fouled the membrane prepared from the original polymer. The preparation conditions, operation conditions, and hydrophilicity of polymer have played an important role in determining the permeation properties of membranes.

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Effect of Toluene Added to Casting Solution on Characteristic of Phase Inversion Polysulfone Membrane (상전환 공정에 의한 폴리설폰막의 제조에 있어 제막용액에 첨가된 톨루엔의 영향)

  • Choi, Seung-Rag;Park, So-Jin;Seo, Bum-Kyoung;Lee, Kune Woo;Han, Myeong-Jin
    • Applied Chemistry for Engineering
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    • v.19 no.6
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    • pp.633-639
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    • 2008
  • Polysulfone membranes were prepared via the phase inversion process. Toluene was added as a nonsolvent additive in the casting solution containing a mixture of polysulfone and n-methylpyrrolidone. When prepared via the diffusion-induced process using isopropanol as a precipitation nonsolvent, the solidified membranes revealed a similar asymmetric structure irrespective of the addition of toluene, presenting both a dense skin layer and a sponge-like support layer. The added toluene played a role of enhancing liquid-liquid phase separation of the casting solution, and skin layer thickness of a prepared membrane increased with toluene content in the casting solution. On membrane performance, the solute rejection showed a uniform behavior irrespective of the addition of toluene. However, in spite of the significant increase in dense skin layer thickness, the water permeation through the membrane prepared with 60 wt% toluene revealed five times as much flux, compared with that of the membrane prepared without toluene additive.

Study on the Removal of Water Vapor Using PEI/PEBAX Composite Hollow Fiber Membrane (PEI/PEBAX 복합 중공사 막을 이용한 수분 제거에 관한 연구)

  • Park, Chun-Dong;Hyung, Chan-Heui;Kim, Kee-Hong;Choi, Won-Kil;Park, Yeong-Seong;Lee, Hyung-Keun
    • Membrane Journal
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    • v.23 no.2
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    • pp.119-128
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    • 2013
  • In this research, PEI/PEBAX composite hollow fiber membrane was used for the removal of water vapor from gases. PEI (Polyetherimide) substrate membrane was spinned by dry-wet phase inversion method and coated with PEBAX (Polyether block amides) 3533 and PEBAX1657. Fabricated fibers typically had an asymmetric structure of a dense top layer supported by a sponge-like substructure through scanning electron microscopy (SEM). $H_2O/N_2$ mixture gas was used to compare the performance of separation according to temperature, pressure and water activity. The results of PEBAX3533 and PEBAX1657 composite membranes respectively showed $H_2O/N_2$ selectivity of 61.7~118.5 and 85.3~175.4 according to operating conditions. PEBAX3533 composite hollow fiber membranes module showed the water vapor removal of 90%.

Morphology control in PVDF membranes using PEG/PVP additives and mixed solvents

  • Rajabi, Shima;Khodadadi, Foroogh;Mohammadi, Toraj;Tavakolmoghadam, Maryam;Rekabdar, Fatemeh
    • Membrane and Water Treatment
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    • v.11 no.4
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    • pp.237-245
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    • 2020
  • The effects of the mixed two solvents, Dimethylacetamide (DMAc) and Dimethylformamide (DMF), and Polyethylene glycol (PEG) and Polyvinylpyrrolidone (PVP) as additives on performance of Polyvinylidene fluoride (PVDF) membranes were studied. Initially, PEG200 was used as a primary additive at fixed percentage of 5% wt. PVP was then blended with PEG200 in different concentrations. PVDF and DMAc were used as polymer and solvent in the casting solutions, respectively. To control the diffusion rate of PVP in the presence of PEG200 and PVP blend, mixtures of DMAc and DMF were used as the mixed solvent in the casting solutions. Asymmetric PVDF membranes were prepared via phase inversion process in a water bath and the effects of two additives and two solvents on the membrane morphology, pure water flux (PWF), hydrophilicity and rejection (R) were investigated. Attenuated Total Reflection Fourier Transform Infrared Spectra (ATR-FTIR) analysis was used to show the residual PVP on the surface of the membranes. Atomic Force Microscopy (AFM) was utilized to determine roughness of membrane surface. The use of mixed solvents in the casting solution resulted in reduction of PVP diffusion rate and increment of PEG diffusion rate. Eventually, PWF and R values reduced, while porosity and hydrophilicity increased.

A Study on the Concentration Polarization Layer Resistance in Ultrafiltration of Macromolecular Solutions (고분자 용액의 한외여과에서 농도분극층 저항에 관한 연구)

  • 염경호
    • Membrane Journal
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    • v.2 no.1
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    • pp.59-66
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    • 1992
  • The experimental studies were carried out on ultrafiltration of PEG #6000 and dextran 70T macromole¬cules. using an asymmetric cellulose acetate membrane in a cross flow plane type cell. Effects of pressure difference. feed concentration were studied on permeate flux and observed rejection for both the macromole¬cules. and the concentration polarization layer resistance $R_{b1}$ on permeate flux was analysed. The concentration polarization layer resistance $R_{b1}$ was correlated with the average macromolecule concen¬tration $C_{b1}$ in polarization layer. The resulting dimensionless correlation was expressed as : $\frac{R_{b1}}{{R_m}}=\alpha[\frac{\rho_{b1}}{C_{b1}}]^\beta$

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