• Membrane and Water Treatment
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• v.11 no.3
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• pp.223-229
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• 2020

Here magnetic iron oxide particles (MIOPs) were synthesized under atmospheric air and which size was controlled by regulating the flow rate of alkali addition and used for efficient removal of bovine serum albumin (BSA) from water. The MIOPs were characterized using field-emission scanning electron microscopy (FE-SEM), Fourier transformation-Infrared spectroscopy (FT-IR) and vibrating sample magnetometer (VSM). The results revealed a successful preparation of the MIOPs. The removal efficiency for BSA using MIOPs was found to be about 100% at lower concentrations (≥ 10 mg/L). The maximum adsorption of 64.7 mg/g for BSA was achieved as per the Langmuir adsorption model. In addition, microfiltration membrane for removal of BSA as model protein organic foulant is also studied. The effect of various MIOPs adsorbent sizes of 210, 680 and 1130 nm on the absorption capacity of BSA was investigated. Water permeability of the BSA integrated with the smallest size MIOPs membrane was increased by approximately 22% compared by the neat BSA membrane during dead-end filtration. Furthermore, the presence of small size MIOPs were also effective in increasing the permeate flux.

• Journal of Environmental Science International
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• v.17 no.1
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• pp.119-128
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• 2008

Laboratory analytical results of 22 sets of hydrophobic adsorbent coils containing surface soil-vapor and two soil samples collected by conventional intrusive method from each boring location at two active dry cleaning facilities in the State of Illinois, U.S.A, were presented to evaluate the performance of soil-vapor survey. The most critical factor to determine the effectiveness of soil-vapor survey is the distance from the soil-vapor sampling device to the actual contamination, which is a function of soil porosity, permeability, primary lithology, and other geological and hydrogeological site-specific parameters. Also this factor can be affected by the history of contaminant-generating operations. The laboratory analytical results in this study showed longer dry cleaning operation history (i.e., 50 years) and presence of fine sand at the beneath Site B allow the contaminants to migrate farther and deeper over a fixed time compared to Site A(i.e., 35 years and silty clay) so that the soil-vapor survey is not likely the most effective environmental site investigation method alone for Site B. However, for Site A, the soil-vapor survey successfully screened the site to identify the location reporting the highest soil concentration of chlorinated solvents.

• Proceedings of the Membrane Society of Korea Conference
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• 1993.10a
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• pp.58-58
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• 1993

Pervaporation has become important as a method to separate liquid mixtures, sepecially azeotropic and close boiling-point mixtures. Especially, water-alcohol separations have been carried out a lot because of the practical interests in the industries. However, outstanding membranes with high selectivity and high permeability have not been available in common use yet. In order to separate selectively out the water mixed with alcohols with an aim of the purification of the alcohols, a membrane has tO have excellent affinity to water. Among the hydrophilic polymers, polyacrylic acid and poly(vinyl alcohol) are used widely. In recent years, ionomers and polyion complexes, better hydrophitic materials, start to be used. The polyion complex membranes, consisting of polyacrylic acid (PAA) and polycation, showed excellent permeation rates and selectivities. It was known that among the polycations, ioneries, which have quaternary ammonium groups in the backbone chain, were more effective in giving membranes of higher permselectivities. On this base, syntheses and characterizations of the polycations, with different chemical structures from the published ones, for the polyion complex membrane formation were studied in this paper.

• 한국전산유체공학회:학술대회논문집
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• 2004.03a
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• pp.183-189
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• 2004

The flow and the heat transfer about the cross-flow fin-tube heat exchanger in an out-door unit of a heat pump system has been numerically Investigated. Using the general purpose analysis code, FLUENT, the Navier-Stokes equations and the energy equation are solved for the three dimensional computation domain that encompasses multiple rows of the fin-tube. The temperature on the fin and tube surface is assumed constant but compensated later through the fin efficiency when predicting the heat-transfer rate. The contact resistance is also taken into consideration. The flow and temperature fields for a wide range of inlet velocity and fin-tube arrangements are examined and the results are presented in the paper. The details of the flow are very well captured and the heat transfer rate for a range of inlet velocity is in excellent agreement with the measured data. The flow solution provides the effective permeability and the inertial resistance factor of the heat exchanger if the exchanger were to be approximated by the porous medium. This information is essential in carrying out the global flow field calculation which, in turn, provides the inlet velocity lot the microscopic temperature-field calculation of the heat exchanger unit.

• Journal of the Korean Society of Clothing and Textiles
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• v.18 no.5
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• pp.674-681
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• 1994

In this study, four kinds of vapor-permeable waterproofed fabrics were selected and their properties and the changes of properties were investigated after laundering, petroleum drycleaning or tetrachloroethylene drycleaning (each 1, 5, 10 times). The results were as follows: 1) In the water resistance, only Gore Tex satisfied its minimum property requirements, $1.0kg/cm^2$ It decreased after laddering and drycleaning. Hipora-1000, Hipora-2000, Aitac decreased slightly by petroleum drycleaning and Gore Tex decreased slightly by all three methods. 2) In the moisture vapor transmission, three except Hipora-2000 satisfied its minimum property requirement, $4000g/m^2{\cdot}24hr$.24hr. After laundering and drycleaning, it increased regardless of cleaning methods. 3) In the water repellency, Hipora-lOOG, Hipora-2000 were not almost decreased after laundering and drycleaning. Aitac decreased slightly by petrolem drycleaning and Gore Tex decreased slightly by laundering and petroleum drycleaning. 4) Air permeability of Aitac increased with increasing of cleaning times regardless of cleaning methods. 5) In the bond strength, only Gore Tex dissatisfied its minimum property requirements, 250g/cm. Regardless of cleaning method, bond strength decreased with increasing of cleaning times. 6) Color difference was large in case of Hipora-1000 by laundering, Hipora-2000 by laundering and tetrachloroethylene drycleaning Aitac by tetrachloroethylene drycleaning, Gore Tex by laundering. To diminish property change of vaper-permeable waterproofed fabric, petroleum drycleaning is more effective than laundering and tetrachloroethylene drycleaning.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.11 s.158
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• pp.1572-1582
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• 2006

In this study, in order to compare a Tencel/cotton and a Tencel/Cotton/PET as Tencel blended fabrics with a Tencel fabric, the fabric samples were treated with chitosan after NaOH pretreatment and enzyme treatment thereof, And then its adherent efficiency was enhanced by using a crosslinking agent. After that, it was treated with a softener. In chitosan treatment, the functions of moisture regain, tensile strength, air permeability and crease resistance were more improved in the Tencel blended fabrics than in the Tencel fabric. Thus, it may be thought that the physical properties of the Tencel blended fabrics were more effectively modified than those of the Tencel fabric. And the friction charged voltage was very much reduced in all samples, so that chitosan treatment was effective for prevention of electrostatic charge. Further, chitosan finishing treatment improved remarkably the antibacterial activity in all samples regardless of the type of strains.

• Journal of Applied Biological Chemistry
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• v.56 no.3
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• pp.171-177
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• 2013

Efficient extraction of total proteins from soil microorganisms is tedious because of small quantity. In this regard, an improved method for extraction of whole cell proteins is developed from soil microorganisms, Saccharomyces cerevisiae and Pichia pastoris. of which the cell wall are very strong. Pretreatment with NH4OH prior to the final extraction using NaOH/SDS was tried under the basis that ammonium ion was possible to enhance the permeability and/or to weaken the yeast cell walls. The pre-treatment of yeast cells with NH4OH drastically enhanced the protein extraction when it was compared with control (without NH4OH pre-treatment). At the pre-treatment of 0.04 N NH4OH at pH 9.0, about 3 fold of proteins was obtained from p. pastoris. Ammonium hydroxide appears to penetrate into the yeast cell walls more readily at basic pH. The effect of NH4OH pretreatment was pH dependent. The methods developed in this experiment might be applicable for an effective extraction of yeast proteins for the purpose of biochemical studies, especially proteomic analysis.

• Membrane and Water Treatment
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• v.11 no.2
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• pp.131-139
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• 2020

The current study focused on the preparation of low-cost PVC-based adsorbing membrane. Metakaolin, as available adsorbent, was embedded into the PVC matrix via solution blending method. The as-prepared PVC/metakaolin mixed matrix membranes were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM), pure water permeability and contact angle measurements. The results confirmed the improvement of PWP and hydrophilicity due to the presence of metakaolin in the PVC matrix. Additionally the structure of PVC membrane was changed due to the incorporation of metakaolin in the polymer matrix. The static adsorption capacity of all samples was determined through dye removal. The effect of metakaolin dosage (0-7%) and pH (4, 8, 12) on dye adsorption capacity was investigated. The results depicted that the highest adsorption capacity was achieved at pH of 4 for all samples. Additionally, adsorption data were fitted on Langmuir, Freundlich, and Temkin models to determine the appropriate governing isotherm model. Finally, the dynamic adsorption capacity of the optimum PVC/metakaolin membrane was studied using dead-end filtration cell. The dye removal efficiency was determined for pure PVC and PVC/metakaolin membrane. The results demonstrated that PVC/metakaolin mixed matrix membrane had a high adsorption capacity for dye removal from aqueous solution.

• Journal of Korea Technology Innovation Society
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• v.2 no.2
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• pp.290-308
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• 1999

In this study a system for the treatment or recyling of organic wastes from both urban and rural area was recommended. It was developed based on the resource recovery system regarding human being by four tectnologies; forage, methane production, high-grade composting and complete decomposition. High quality compost can be produced by combining several kind of wastes produced from urban and agricultural areas. High quality compost must possess not only general characteristics of ordinary compost, but also a superior ability to improve the soil properties and must contain more nutrients for plant. Cedar chips were recommended as the main bulking agent to adjust moisture contents and air permeability. Charcoal and zeolite can be used not only as the second bulking agent but also as fertilizer for improve the soil amendment. Complete decomposition of organic wastes is defined by organic matter being completely converted to $CO_2$ and water. All the input water was evaporated by the heat produced through the oxidation of organic matter, In the present study, the complete treatments were successfully achieved for Shochu wastewater, swine wastes, thickened excess sewage sludge, wastes produced by Chinese restaurant and anaerobic digested sludge. First of all, recycling center of organic wastes should be established for the protect the environments and effective recovery of organic resources. This may means the way to derive the recovery of human value.

• Geomechanics and Engineering
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• v.16 no.1
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• pp.71-83
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• 2018

Compacted bentonites were chosen as the backfill material and buffer in high level nuclear waste disposal due to its high swelling pressure, high ion adsorption capacity and low permeability. It is essential to estimate the swelling pressure in design and considering the safety of the nuclear repositories. The swelling pressure model of expansive clay colloids was developed based on Gouy-Chapman diffuse double layer theory. However, the diffuse double layer model is effective in predicting low compaction dry density (low swelling pressure) for certain bentonites, and invalidation in simulating high compaction dry density (high swelling pressure). In this paper, the new relationship between nondimensional midplane potential function, u, and nondimensional distance function, Kd, were established based on the Gouy-Chapman theory by considering the variation of void ratio. The new developed model was constructed based on the published literature data of compacted Na-bentonite (MX80) and Ca-bentonite (FoCa) for sodium and calcium bentonite respectively. The proposed models were applied to re-compute swelling pressure of other compacted Na-bentonites (Kunigel-V1, Voclay, Neokunibond and GMZ) and Ca-bentonites (FEBEX, Bavaria bentonite, Bentonite S-2, Montigel bentonite) based on the reported experimental data. Results show that the predicted swelling pressure has a good agreement with the experimental swelling pressure in all cases.