• Membrane Journal
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• v.15 no.2
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• pp.147-156
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• 2005

It is well-known that polyethersulfone (PES) has high $CO_2$ selectivity over $N_2\;(or\;CH_4)$ and excellent pressure resistance of $CO_2$ plasticization among muy commercialized engineering plastics[1-4]. Asymmetric PES hollow fiber membranes for flue gas separation were developed by dry-wet spinning technique. The dope solution consists of PES, NMP and acetone. Water and water/NMP mixtures are used in outer and inner coagulants, respectively. Gas permeation rate (i.e., permeance) and $CO_2/N_2$ selectivity were measured with pure gas, respectively and the micro-structure of hollow fiber membranes was characterized by scanning electron microscopy. The effects of polymer concentration, ratio of NMP to acetone, length of air gap, evaporation condition and silicone coating were investigated on the $CO_2/N_2$ separation properties of the hollow fibers. Optimized PES hollow fiber membranes exhibited high permeance of $25\~50$ GPU and $CO_2/N_2$ selectivity of $30\~40$ at room temperature and have the apparent skin layer thickness of about $0.1\;{\mu}m$. The developed PES hollow fiber membranes, would be a good candidate suitable for the flue gas separation process.

• Membrane Journal
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• v.15 no.1
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• pp.1-7
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• 2005

Polymer electrolyte membranes containing polysilsesquioxane (PSQ) spheres were prepared with the blend of sulfonated poly(ether ether ketone) (SPEEK) (60%) and poly(ether sulfone) (PES) (40%). The amount of PSQ spheres was fixed at 10 wt%. The prepared polymer electrolyte membranes were characterized in terms of methanol permeability, proton conductivity, and ion exchange capacity. In all cases, both methanol permeability and proton conductivity of the polymer electrolyte membranes containing PSQ spheres were lower than the values of Nafion 117 and higher than those of SPEEK/PES (6:4) blend without PSQ spheres. The experimental results indicated that the polymer electrolyte membranes containing MS64 and VTMOS spheres were the best choice in terms of the ratio of proton conductivity to methanol permeability.

• Membrane Journal
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• v.14 no.1
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• pp.57-65
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• 2004

The effect of porous support layer resistance and PDMS (polydimethylsiloxane) coating thickness on ethylene/nitrogen separation of composite membranes was studied with the model of Pinnau and Wijmans〔1〕. To control the support resistance (or permeance), PES porous membranes were prepared by phase inversion process with various PES/NMP dope concentrations. The thickness of selective PDMS top layer was controlled by using a spin coater. Its cross-section and coating thickness were observed by scanning electron microscope (SEM). Pure gas permeation test was done with ethylene and nitrogen, respectively. The experimental result for olefin/nitrogen separation process matched well with theoretical result from the model used. The result shows that optimization between PDMS coating thickness and support resistance is important to get PDMS composite membranes with best performance.

• Membrane Journal
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• v.20 no.3
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• pp.235-240
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• 2010

The aim of this paper is to evaluate and compare the performances of forward osmosis (FO) membranes using different materials. The FO membranes were synthesized using interfacial polymerization method on hydrophobic polysulfone (PSf) and relatively hydrophilic polyethersulfone (PES) supports. The FO performance such as flux and back diffusion was measured. The resulting fluxes of PSf and PES FO membranes were $4.3\;L/m^2hr$ and $17.8\;L/m^2hr$, respectively. The flux of the PES FO membrane was higher than that of the PSf FO membrane. The results indicated that hydrophillictity of the support membrane is important for increasing flux in FO process. Moreover, with decreasing the support layer thickness, flux increased considerably.

• Environmental Engineering Research
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• v.19 no.4
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• pp.339-344
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• 2014

Different types of polyethersulfone (PES) support layer for a thin film composite (TFC) membrane were synthesized under various synthesis conditions using the phase inversion method to study the combined effects of substrate, adhesive, and pore former. The permeability, selectivity, pore structure, and morphology of the prepared membranes were analyzed to evaluate the membrane performance. The combined use of substrate, adhesive, and pore former produced a thinner dense top layer, with more straight finger-like pores. The pure water permeation (PWP) of the optimized PES membrane was $27.42L/m^2hr$ (LMH), whereas that of bare PES membrane was 3.24 LMH. Moreover, membrane selectivity, represented as divalent ion ($CaSO_4$) rejection, was not sacrificed under the synthesis conditions, which produced the dramatically enhanced PWP. The high permeability and selectivity of the PES membrane produced under the optimized synthesis conditions suggest that it can be utilized as a potential support layer for TFC membranes.

• Membrane and Water Treatment
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• v.9 no.1
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• pp.43-51
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• 2018

Hollow fiber (HF) membranes are gaining wide interest over flat membranes due to their compaction and high area to surface volume ratio. This work addresses the fabrication of HF from polysulfone (PS) and polyethersulfone (PES) using N-methylpyrrolidone (NMP) as solvent in addition to other additives to achieve desired characteristics. The semi-pilot spinning system includes jacketed vessel, four spinneret block, coagulation and washing baths in addition to dryer and winder. Different parameters affecting dry-wet spinning phase inversion process were investigated. Dope compositions of PES, NMP and polyvinyl pyrrolidone (PVP) of varying molecular weights as additive were addressed. Some critical parameters of importance were also investigated. Those include dope flow rate, air gap, coagulation & washing baths and drying temperatures. The measured dope viscosity was in the range from 1.7 to 36.5 Pa.s. Air gap distance was adjusted from 20 to 45 cm and coagulation bath temperature from 20 to $46^{\circ}C$. The HF membranes were characterized by scanning electron microscope (SEM), atomic force microscope (AFM) and mechanical properties. Results indicated prevalence of finger like structure and average surface roughness from about 29 to 78.3 nm. Profile of stress strain characteristics revealed suitability of the fibers for downstream interventions for fabrication of thin film composite membrane. Different empirical correlations were formulated which enable deeper understanding of the interaction of the above mentioned variables. Data of pure water permeability (PWP) confirmed that the fabricated samples fall within the microfiltration (MF)-ultrafiltration (UF) range of membrane separation.

• Applied Chemistry for Engineering
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• v.34 no.1
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• pp.51-56
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• 2023

Composite membranes consisting of TiO₂ nanoparticles (NPs) and porous polymers have been widely utilized in photocatalytic water treatment because the composite membranes can allow an easy recovery of NPs after the photocatalytic reaction as well as the reduction of fouling in the membrane. However, the photocatalytic efficiency of the immobilized TiO₂ NPs in the composite membranes has been discussed to a limited degree. In this study, we prepared polyethersulfone (PES)/TiO₂ composite membranes to study the photocatalytic decomposition of organic dyes under light illumination. The decomposition kinetics of dye molecules by the PES/TiO₂ composite membranes and colloidal TiO₂ NPs have been compared to discuss the photocatalytic efficiency of NPs before and after their immobilization on the polymer membrane.

• Membrane Journal
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• v.10 no.3
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• pp.130-138
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• 2000

Polyethersulfone (PES) asymmetric membranes for gas separation were prepared by dry/wet phase inversion method and their separation properties for CO$_2$ and N$_2$ gases were investigated. The effects of important variables such as composition of casting solution and evaporation time in preparation of asymmetric gas membrane on membrane morphology and the separation properties were analyzed and the optimum condition of membrane preparation was established. To compensate the defects like pinholes existed on skin layer of the membrane prepared, the membranes were coated with silicone resin. By comparing separation properties after coating with those before coating, we found that the coating of silicone resin was effective to enhance the separation properties. The casting solution mainly used in this study consisted of PES, N-methyl-2-pyrrolidone, acetone, ethanol and distilled water was used as coagulation agent. It was shown that the selectivity for CO$_2$/N$_2$ was getting higher but the permeability decreases, as the contents of PES and volatile organic solvent and evaporation time increased. The selectivity for CO$_2$/N$_2$ and permeability of CO$_2$ of the membrane prepared under the optimum condition were found to be 61 and 21 GPU, respectively.

• Membrane Journal
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• v.23 no.1
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• pp.80-91
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• 2013

Metal-templated condensation of cyclohexanedione dioxime and phenylboronic acid in the presence of Fe(II) sulfate heptahydrate proceeds cleanly in methanol to furnish the Fe(II) clathrochelate. An organic/inorganic hybrid membranes composed of Fe(II) clathrochelate and polyethersulfone was prepared by using phase inversion method. For membrane preparation, the Fe(II) clathrochelate was highly soluble (3~5 g/L) in DMF, NMP, and DMAc, which meets the requirements for the solubility of metal complexes in polar aprotic solvent used in membrane preparation. It was stable even in the presence of strong acids, such as trifluorosactic acid (pKa = 0.3). It was characterized by UV-vis spectroscopy, and their stability in solution phase studied in the presence of (i) strong acids or (ii) competing chelates. Organic/inorganic hybrid membranes were prepared with polyethersulfone, polyvinylpyrrolidone, p-toluenesulfonic acid, Fe(II) clathrochelate and DMF by using nonsolvent induced phase inversion method. The addition of Fe(II) clathrochelate leads increase of surface pore density, mean pore size and flux. We can obtain highly asymmetric membranes by addition of Fe(II) clathrochelate.

• Membrane Journal
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• v.17 no.1
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• pp.23-30
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• 2007

Protein affinity membranes based on polyethersulfone (PES) and bovine serum albumin (BSA) were prepared by using an electrospinning method. The changes in the size of nanofiber according to the various conditions of electrospinning (concentration of spinning solution, voltage, flow rate, tip to collector distance) were investigated, and the preparation conditions of the affinity membrane were optimized. XPS and FT-IR results showed the firm incorporation of BSA with PES. It was found PES-BSA nanofibers could be prepared at the temp. of $20{\sim}22^{\circ}C$ and humidity of $45{\sim}55%$. The size of nanofibers increased with increase of the content of PES in the spinning solution while BSA did not affect much to the size of nanofiber. It was also revealed that the narrow size distribution of nanofiber could be obtained with PES 7 wt%, BSA 0.7 wt%, HFP 92.3 wt% at the electrospinning conditions of 1 mL/hr, 10 cm TCD, and 10 kV.