• Journal of The Korean Association For Science Education
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• v.22 no.3
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• pp.444-454
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• 2002

In this study, we analyzed the explanation of the concepts related to osmotic pressure and semipermeable membrane that were represented in chemistry and biology textbooks of high school and general course of college. There were 4 types of explanation in osmotic pressure and 3 types of semipermeable membrane concept. Students can understand the concepts with different meaning because there are different viewpoints on the explanations of the concepts. We must consider the various types of explanation when we design science textbooks because these confusions disturb students' understanding of the concepts.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1655-1659
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• 2008

Using numerical models, we investigated the efficiency of toxin removal using pulsatile flow in blood purification systems that use semipermeable membranes. The model consisted of a three-compartmental mass transfer model for the inside body and a solute kinetics model for the dialyzer. The model predicted the toxin concentration inside the body during blood purification therapy, and the toxin removal efficiencies at different flow configurations were compared quantitatively. According to the simulation results, the clearances of urea and ${\beta}_2$ microglobulin (B2M) using a pulsatile pump were improved by up to 30.9% for hemofiltration, with a 2.0% higher urea clearance and 4.6% higher B2M clearance for high flux dialysis, and a 3.9% higher urea clearance and 8.2% higher B2M clearance for hemodiafiltration. These results suggest that using a pulsatile blood pump in blood purification systems with a semipermeable membrane improves the efficacy of toxin removal, especially for large molecules and hemofiltration treatment.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.5
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• pp.553-559
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• 2016

There has been increasing global interest in the environmental pollution problems produced by fossil fuel consumption and greenhouse gas emissions. In order to tackle these issues, new renewable energy such as solar, wind, bio gas, fuel cell and pressure retarded osmosis(PRO) have been developed extensively. Among these energy sources, PRO is one of the salinity gradient power generation methods. In PRO, energy is obtained by the osmotic pressure generated from the concentration difference between high and low concentration solutions separated by a semipermeable membrane. The development for high power density PRO membranes is imperative with the purpose of commercialization. This study investigates development of thin film composite PRO membrane and spiral wound module for high power density. Also, the influence of membrane backing layer on power density was identified, and the characteristic factors of PRO membranes was determined. Different backing layers were used to improve power density. As expected, the PRO membrane with more porous backing layer showed higher power density.

• Membrane Journal
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• v.30 no.5
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• pp.293-306
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• 2020

Increasing harmful effects of climate change, such as its effect on water scarcity, has led to a focus on developing effective water purification methods to obtain pure water. Additionally, rising levels of water pollution is increasing levels of environmental degradation, calling for sources of water treatment to remove contaminants. To purify water, osmotic processes across a semipermeable membrane can take place, and recent studies are showing that incorporating nanoparticles, including carbon quantum dots (CQDs), graphene carbon dots (GQDs), and graphene oxide quantum dots (GOQDs) are making thin film composite (TFC) membranes more effective by increasing water flux while maintaining similar levels of salt rejection, increasing the hydrophilicity of the membrane surface, showing bactericidal properties, exhibiting antifouling properties to prevent accumulation of bacteria or other microorganisms from reducing the effectiveness of the membrane, and more. In the review, the synthesis process, applications, functionality, properties, and the role of several types of quantum dots are discussed in the composite membrane for water purification.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.4
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• pp.285-292
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• 2021

Osmotic power is to produce electric power by using the chemical potential of two flows with the difference of salinity. Water permeates through a semipermeable membrane from a low concentration feed solution to a high concentration draw solution due to osmotic pressure. In a pressure retarded osmosis (PRO) process, river water and wastewater are commonly used as low salinity feed solution, whereas seawater and brine from the SWRO plant are employed as draw solution. During the PRO process using wastewater effluent as feed solution, PRO membrane fouling is usually caused by the convective or diffusive transport of PRO which is the most critical step of PRO membrane in order to prevent membrane fouling. The main objective of this study is to assess the PRO membrane fouling reduction by pretreatment to remove organic matter using coagulation-UF membrane process. The experimental results obtained from the pretreatment test showed that the optimum ferric chloride and PAC dosage for removal of organic matter applied for the coagulation and adsorption process was 50 mg/L as FeCl₃ (optimum pH 5.5). Coagulation-UF pretreatment process was higher removal efficiency of organic matter, as also resulting in the substantial improvement of water flux of PRO membrane.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.4
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• pp.303-310
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• 2017

Pressure retarded osmosis(PRO) has attracted much attention as potential technology to reduce the overall energy consumption for reverse osmosis(RO) desalination. The RO/PRO hybrid process is considered as the most logical next step for future desalination. The PRO process aims to harness the osmotic energy difference of two aqueous solutions separated by a semipermeable membrane. By using the concentrated water(RO brine) discharged from existing RO plants, the PRO process can effectively exploit a greater salinity gradient to reduce the energy cost of processing concentrated water. However, in order to use RO brine as the draw solution, PRO membrane must have high water flux and enough mechanical strength to withstand the high operational pressure. This study investigates the development of a thin film composite PRO membrane and spiral wound module for high power density. Also, the influence of membrane backing layer on the overall power density was studied using the characteristic factors of PRO membranes. Finally, the performance test of an 8-inch spiral wound module was carried out under various operating conditions(i.e. hydraulic pressure, flow rate, temperature). As the flow rate and temperature increased under the same hydraulic pressure, the PRO performance increased due to the growth of water permeability coefficient and osmotic pressure. For a high performance PRO system, in order to optimize the operating conditions, it is highly recommended that the flow pressure be minimized while the flow rate is maintained at a high level.

• Journal of Pharmaceutical Investigation
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• v.36 no.1
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• pp.11-17
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• 2006

The objective of this study was to confirm the effect of the type of dissolution media and paddle speed on nifedipine (ND) release profile from osmotic granule and the storage stability. Osmotic granule was manufactured by fluidized bed coating method. At each coating step, morphology of osmotic granule was differed. The size of osmotic granule was $750\;{\mu}m$ at 3 wt% membrane thickness. ND release was changed in diverse dissolution media, paddle speed. ND release is governed by not only osmotic pressure but diffusion from osmotic granule. ND release from osmotic granule decreased as storage period increased. These may be caused by liquid excipient which has low molecular weight. Storage stability of osmotic granule could be improved by removing liquid excipient from semipermeable membrane.

• Textile Coloration and Finishing
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• v.10 no.5
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• pp.56-62
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• 1998

In the prior study, the dyeing behaviors of Milling Cyanine 5R on silk fiber in aqueous dyeing liquor including small amount of organic compounds were investigated. The most effective compound was acetophenone which increased dye uptake as well as dyeing rate. In this study, the role of the acetophenone in dyeing of silk with Milling Cyanine 5R was studied. By addition of acetophenone into the dye solution, the molar absorptivity of Milling Cyanine 5R increased, and the wavelength of maximum absorption was shifted to longer wavelength, namely bathochromic shifted. This shows that the acetophenone prevents the dye to aggregate, and increases the number of monomeric dye molecule relative to the dye solution without acetophenone. This fact was also confirmed by the increase of the permeation rate of the dye through cellulose semipermeable membrane from the dye solution including the acetophenone. From these results, the acetophenone acts as a prohibitor of dye aggregation, increases the number of monomeric dye molecules even at relatively low temperature, and makes the dyes penetrate into the fiber easier.

• Environmental Analysis Health and Toxicology
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• v.16 no.4
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• pp.171-179
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• 2001

A new passive sampler was developed, improving SPMD (Semipermeable Membrane Devices) that contained triolein in nonporous, low-density polyethylene layflat tubing. Experiments to measure PAHs concentration were carried out at four sites (Dukpo, Sochi, Sohwonggando, Yeonmok) on the southern coast of Korea that were contaminated by oil spills. Passive samplers were deployed at 4 and 8 week intervals at each site. Results showed that bioconcentration levels of PAHs were increased in proportion to exposure duration from all sample sites and accumulation in the passive sampler was much higher than in biota at the Dukpo site. Results of these tests suggest that new passive sampler is a useful tool for measuring bioconcentration organic compounds in aquatic environments.

• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.63-67
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• 1989

In order to examine the suppressive effect of dietary fiber toward the intestinal absorption of lead, an in vitro absorption test using a semipermeable membrane was undertaken. Among dietary fiber components, cellulose showed no suppressive effect, guar gum and carboxymethyl-cellulose, a slight effect whereas citrus pectin and sodium alginate exhibited a remarkable effect. Among fibrous foods tested, rice bran, wheat bran, Chinese cabbage, radish and tangle had a higher suppressive effect while mandarin orange, apple and laver showed a lower effect.