• Membrane and Water Treatment
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• v.7 no.3
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• pp.257-275
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• 2016

The enantiomeric and racemic effects of tartaric acid (TA) on the properties of polysulfone (PSn) ultrafiltration membranes were studied in terms of morphology and hydrophilicity (HPCT) of membrane. Asymmetric membranes were prepared by direct blending of polyvinyl pyrrolidone (PVP) with D-TA and DL-TA in membrane casting solution. FTIR analysis was done for the confirmation of the reaction of PVP and TA in blended membranes and plain PSn membranes. Scanning electron microscope (SEM), field emission scanning electron microscope (FESEM) and atomic force microscopy (AFM) were used for analyzing the morphology and structure of the resulting membranes. The membranes were characterized in terms of pure water flux (PWF), hydraulic permeability and HPCT. PWF increased from $52L/m^2h$ to $79.9L/m^2h$ for plain and D-TA containing PSn membrane, respectively. Water contact angle also found to be decreased from $68^{\circ}$ to $55^{\circ}$. In Additionally, permeation and rejection behavior of prepared membranes was studied by bovine serum albumin (BSA) solution. A considerable increase in BSA flux (from $19.1L/m^2h$ for plain membrane to $32.1L/m^2h$ for D-TA containing membrane) was observed. FESEM images affirm that the pore size of the membranes decreases and the membrane permeability increases from 0.16 to 0.32 by the addition of D-TA in the membrane. D-TA increases the HPCT whereas; DL-TA decreases the HPCT of PSn membrane. PVP (average molecular weight of 40000 Da) with D-TA (1 wt%) gave best performance among all the membranes for each parameter.

• Membrane Journal
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• v.14 no.2
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• pp.108-116
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• 2004

In this study, the pore-filled ion-exchange membranes were prepared by using the asymmetric PVDF membrane as a nascent membrane. First, the solution of PVBCI having the chlorornethylate aryl ring of 80 percents and DABCO was made with the mixed solvent of THF and DU (8:2). These mixed solution was then, filled in the pores of PVDF membrane, and left for a day to complete the gelation. Finally the pore-filled anion-exchange membrane is obtained fallowed by the amination of the remaining chloromethyl groups with trimethylamine (TMA, 40 wt% in water) forming the positive ammonium ion sites. This 2 step procedure enabled us to produce the pore-filled membranes without change of size, and to control the properties of final membrane with various degree of cross-linking. The results of SEM and AFM showed the polyelectrolyte existed in the pores of nascent membrane as a certain configuration. From the investigation of the solvent affecting much to the permeability and rejection, it was found that the membranes using mixed solvent of THE and DMF (8:2) showed better performances than the membranes produced by THF only. The result of an investigation for the water permeability of the final membrane at low pressure (100 Kpa) showed a typical ultrafiltration membrane's permeability (8 ∼ 10 kg/$m^2$hr) and good values of rejection (55∼60 percent).

• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.287-299
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• 2014

Bicarbonate anion ($HCO_3{^-}$) takes the role of major buffer systems in our body by maintaining the pH at 7.4. Epithelial $HCO_3{^-}$ secretion also hydrolyzes the mucus which protects body from noxious infections. It has been widely known that such infections are closely related to $HCO_3{^-}$ permeability through membrane and, thus, increasing the $HCO_3{^-}$ permeability is essential. To evaluate the $HCO_3{^-}$ permeability through ion channels, the free energy changes relevant to ion pumping are calculated with the Integral Equation Formalism-PCM (IEF-PCM) theory. Molecular structures of various anions including $HCO_3{^-}$ were optimized with the density functional theory at the level of B3LYP/6-311++G(d,p) in gas and solution phase. In addition, the anion permeability is significantly influenced by the relative size of the anion and pore. We introduce a shifted volume factor model that describes the pore size effect when the charged solutes transfer through ion channels. We found excellent agreement between experimental and calculated permeability when our novel model of the size effect was taken into account to.

• Journal of Plant Biology
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• v.31 no.2
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• pp.113-119
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• 1988

The effects of the defoliant and desiccant dimethipin(2,3-dihydro-5,6-dimethyl-1,4-dithiin-1,1,4,4-tetraoxide) on the passive permeability and osmotic ground value of onion(Allium cepa L.) epidermal cells were investigated by plasmometric method. The osmotic ground value and the water permeability of onion epidermal cells were decreased by 9.8% and 41.2%, respectively, and the passive permeabilities of nonelectrolytesurea, methylurea, ethylurea and malonamide-were also decreased by the range of 15.7%∼57.8% after treatment with 10-3M dimethipin. After treatment with 10-4M dimethipin, the osimotic ground value and the solute permeability of onion epidermal cells were also decreased by 3.7% and 24.5%∼48.8%, respectively, but the water permeability of onion epidermal cells was increased by 8.3%. It was suggested that dimethipin treatment modified the cell membrane of onion epidermis.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2001.05a
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• pp.140-140
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• 2001

Porins are major outer membrane proteins which produce non-specific aqueous channels across the membrane that permit the diffusion into the bacterial cells of hydrophilic compounds including sugars, amino acids, and antibiotics. In some gram-negative organisms, antibiotic resistance can be induced by mutational loss of channel that causes a decrease in outer membrane permeability. (omitted)

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• v.5 no.1
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• pp.14-21
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• 2002

In the present paper, the hydrodynamic properties of a Rahmen-type, flexible, porous breakwater interacting with obliquely or normal- incident small amplitude waves are numerically investigated. This system is composed of dual vertical porous membranes, hinged at the side edges of a submerged horizontal membrane. The dual vertical membranes are extended downward and hinged at seabed. The effects of permeability, Rahmen-type membrane breakwater geometry, pre-tensions on membranes, relative dimensionless wave number, and incident wave headings are thoroughly examined.

• Proceedings of the Membrane Society of Korea Conference
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• 1992.10a
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• pp.47-48
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• 1992

Polymer containing monomers with pendant phospholipid polar group, 2-(metha-cryloyoxy) ethyl-2-(trimethylammonium) ethyl phosphate(MTP) were synthesized and blood compatibility of the copolymers was evaluated. Good permeability of biocomponents of molecular weight below 10$^4$ through cellulosic membrane coated with the copolymer of 2-(methacryloyoxy) ethyl-2-(tri-methylammonium)ethyl phosphate, butylmethacrylate(BMA), and glycidyl methacrylate(GMA) was observed, (Fig.1).

• Membrane and Water Treatment
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• v.10 no.4
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• pp.277-286
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• 2019

In 2014, the first demineralization plant, using nanofiltration (NF) membrane coupled with renewable energies was realized at Al Annouar high school of Sidi Taibi, Kenitra, Morocco. This project has revealed difficulties related to the membrane performances loss (pressure increase, flux decline, poor water quality of the produced water and increase of energy consumption), as consequences of membrane fouling. To solve this problem, an autopsy of the membrane was done in order to determine the nature and origin of the fouling. The samples of membrane and fouling were then analyzed by scanning electron microscopy using a scanning electron microscope (SEM) connected with an energy dispersive X-ray (EDX) detection system and X-ray diffractometer (XRD). Moreover, three cleaning solutions (hydrochloric acid, nitric acid and sulfuric acid) were tested and assessed in a single cleaning step to find the suitable one for the fouled membrane to regain its initial permeability and performances. The analysis of the experimental results showed that the fouling layer is mainly composed of calcium carbonate (inorganic fouling). Results showed also that the permeability is improved by the hydrochloric acid cleaning (pH=3) with a cleaning efficiency of 93%. Cleaning efficiency did not exceed 75 % with nitric acid (pH=3) and 40 % with sulfuric acid (pH=3).

• Membrane Journal
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• v.34 no.2
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• pp.140-145
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• 2024

In modern times, when a change in the energy paradigm is required, hydrogen is an attractive energy source. Among these hydrogen purification technologies, technology using a membrane is attracted attention as a technology that can purify high purity hydrogen at low cost. However, palladium(Pd), which is mostly used because of its excellent hydrogen separation performance, is very expensive, so a replacement material is needed. In this study, a alloy membrane was manufactured from an alloy of niobium (Nb), which has high hydrogen permeability but is weak to hydrogen embrittlement, and nickel (Ni) and zirconium (Zr), which have low hydrogen permeability but are highly durable. Hydrogen permeation characteristics were confirmed under conditions of 350~450 ℃ at 1 to 4 bar. The maximum hydrogen permeation flux was 0.69 ml/cm²/min for the Ni₄₈Nb₃₂Zr₂₀ alloy membrane without Pd coating, and 13.05 ml/cm²/min for the Pd coated alloy membrane.

• Korean Chemical Engineering Research
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• v.43 no.4
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• pp.487-494
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• 2005

Nowadays a large amount of wastewater containing metal working fluids and cleaning agents is generated during the cleaning process of parts working in various industries of automobile, machine and metal, and electronics etc. In this study, aqueous or semi-aqueous cleaning wastewater contaminated with soluble or nonsoluble oils was treated using ultrafiltration system. And the membrane permeability flux and performance of oil-water separation (or COD removal efficiency) of the ultrafiltration system employing PAN as its membrane material were measured at various operating conditions with change of membrane pore sizes and soil concentrations of wastewater and examined their suitability for wastewater treatment contaminated with soluble or insoluble oil. As a result, in case of wastewater contaminated with soluble oil and aqueous or semi-aqueous cleaning agent, the membrane permeability increased rapidly even though COD removal efficiency was almost constant as 90 or 95％ as the membrane pore size increased from 10 kDa to 100 kDa. However, in case of the wastewater contaminated with nonsoluble oil and aqueous or semi-aqueous cleaning agent, as the membrane pore size increased from 10 kDa to 100 kDa and the soil concentration of wastewater increased, the membrane permeability was reduced rapidly while COD removal efficiency was almost constant. These phenomena explain that since the membrane material is hydrophilic PAN material, it blocks nonsoluble oil and reduces membrane permeability. Thus, it can be concluded that the aqueous or semi-aqueous cleaning solution contaminated with soluble oil can be treated by ultrafiltration system with the membrane of PAN material and its pore size of 100 kDa. Based on these basic experimental results, a pilot plant facility of ultrafiltration system with PAN material and 100 kDa pore size was designed, installed and operated in order to treat and recycle alkaline cleaning solution contaminated with deep drawing oil. As a result of its field application, the ultrafiltration system was able to separate aqueous cleaning solution and soluble oil effectively, and recycle them. Further more, it can increase life span of aqueous cleaning solution 12 times compared with the previous process.