• 환경위생공학
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• 제12권1호
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• pp.77-83
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• 1997

An experimental research was conducted in order to study the treatment of waste reuse system using the membrane. Cell tester which supplied by Amicon was used to compare the fluxes of various membranes. Specially investigated items in the experiment were carried out by using 5 species of microfiltration membranes as to various MLSS concentrations. From the results, it is recognized from the cell test that 0.2 $\mu $m pore-sized membrane have the most effective performance at 2000mg/L of MLSS, and physical properties of membranes such as strength, deflection, elongation, structure of pore are more important than chemical properties in microfiltration membrane.

• Environmental Engineering Research
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• 제19권4호
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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.

• KSBB Journal
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• 제6권2호
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• pp.135-141
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• 1991

This study thus looks into two treatment processess : i) Anaerobic digester coupled with hollow fibre membrane unit. Treatment of starch waste with anaerobic digester-membrane system was studied. $0.17\m^2$ area of hollow fibre membrane unit of known pore size was immersed into laboratory-scale anaerobic digestion system. The pore size of membrane was varied from 0.03 to $\0.15mu$m. The hydraulic retention time of anaerobic digester was varied from 1.5 to 10 days. The effect of hydraulic retention time on treatment efficiency was significant while effect of membrane size was not significant. The gas production was about 0.74㎥/kg COD treated. The COD removal efficient was about 80-95% depending on the hydraulic retention time. ii ) Crossflow ultrafiltration as post treatment to anaerobic filter. The effluent from anaerobic filter, which had a total COD in the range of 4,500-5,200 mg/L was treated by crossflow ultrafiltration units. The study conducted with different membrane pore size indicated that membrace with 1,000,000 molecular weight cut-off size gave a higher COD removal efficiency in the range of 83-87% while giving a study flux of $120-130 L/\m^2$.h. A study was conducted to see the long term clogging effect of membrane also.

• Membrane and Water Treatment
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• 제13권4호
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• pp.167-172
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• 2022

The analytical results are presented for the mass transfer in a cylindrical pore covering from the macroscale, multiscale to nanoscale owing to the variation of the inner diameter of the pore. When the thickness h_bf of the physically adsorbed layer potentially fully formed on the pore wall is comparable to but less than the inner radius R₀ of the pore, the multiscale flow occurs consisting of both the nanoscale non-continuum adsorbed layer flow and the macroscopic continuum liquid flow; When R₀ ≤ h_bf, the flow in the whole pore is essentially non-continuum; When R₀ is far greater than h_bf, the flow in the whole pore can be considered as macroscopic and continuum and the adsorbed layer effect is negligible.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.46-53
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• 2011

Water is continuously produced in polymer electrolyte membrane fuel cell (PEMFC), and is transported and exhausted through polymer electrolyte membrane (PEM), catalyst layer (CL), microporous layer (MPL), and gas diffusion layer (GDL). The low operation temperatures of PEMFC lead to the condensation of water, and the condensed water hinders the transport of reactants in porous layers (MPL and GDL). Thus, water flooding is currently one of hot issues that should be solved to achieve higher performance of PEMFC. This research aims to study liquid water transport in porous layers of PEMFC by using pore-network model, while the microscale pore structure and hydrophilic/hydrophobic surface properties of GDL and MPL were fully considered.

• 한국염색가공학회지
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• 제21권4호
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• pp.57-62
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• 2009

N-Halamines are compounds which have covalent bonding between nitrogen and halogen. N-Halamine materials possess strong antimicrobial properties against wide spectrum of bacteria. The aim of this study is to prepare N-halamine membranes using m-aramid and poly(vinyl alcohol) (PVA). Surface characteristics using scanning electron microscope (SEM), pore size distribution, liquid permeability and mean pore size were measured to confirm feasibility as membrane. The results indicated that increased PYA portion up to 15% in the m-aramid/PVA blend resulted in improved pore size distribution, liquid permeability as well as mean pore size. Furthermore, antibacterial efficacy of the membranes after chlorination was confirmed and the results showed that bacteria in water were inactivated.

• 멤브레인
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• 제15권2호
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• pp.85-104
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• 2005

Recently, membrane can be prepared by two methods, phase inversion and electrospinning techniques. Phase inversion technique is a conventional but commercially preparation membrane. The most versatile of preparation in this technique is immersion of the cast film into nonsolvent bath, causing dense top layer with a finger-like pattern in the sub layer membrane. The membrane pore size getting from phase inversion is in the range of micro or submicrometer. As a result, it can be used as microfiltration and ultrafiltration applications. A new technique, electrospinning, is introduced for membrane preparation. Nonwoven nanofibrous mat or nanofibrous membrane is obtained. In this technique, electrostatic charge is introduced to the solution jet, causing a thin fiber with high surface area; hence it can be used in the applications where high surface area-to-volume or length-to-diameter ratios are required. Moreover, the pore size can be controlled by controlling the time of electrospinning. Hence, it can be used as a filter for filtering microparticles as well as nanoparticles.

• 상하수도학회지
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• 제16권6호
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• pp.717-725
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• 2002

A bench-scale submerged-type membrane filtration system (SMFS) was constructed to study a feasibility of membrane filtration for solid-liquid separation in water and wastewater treatment processes. In the case of applying the SMFS to a biological wastewater treatment process, so-called membrane bioreactor, aeration underneath membrane modules is usually employed in order to provide oxygen demand for microbial growth as well as to control membrane fouling. A study was investigated the effects of operation parameters by aeration intensity, feed concentration, foulant type and airlift pore size on critical flux. Critical flux tends to increase with aeration rate. Optimal aeration flow rate was found to be 10 L/min/module. Feed concentration and foulant type has a significant effect on membrane fouling and filtration performance. But downward position and pore size of airlift has no a significant effects on membrane fouling and filtration performance.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제26권2호
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• pp.146-153
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• 2000

The purpose of present study is comparing the effect of Teflon Membrane and Nylon Membrane on bone regeneration in rabbit tibia. The 6 defects of $8{\times}8{\times}5mm$ size were drilled with dental handpiece in rabbit tibia, which on left side as an order of Control group(no coverage), Group 1(Nylon $5{\mu}m$ size), Group 3(Nylon $10{\mu}m$ size), and on right side Control group, Group 2($5{\mu}m$ Teflon), Group 4($10{\mu}m$ Teflon). Animals were killed at 7, 10, 14, 42 days to make specimens and observed the difference of healing potentials with light microscopy. The results were as follows ; 1. New bone formation has taken place at 14 days in Guided Bone Regeneration (GBR) group comparing to the Control group of massive inflammatory status. 2. Larger pore membrane allows more favorable healing potentials. Bone formation started earlier in larger membrane pore groups than smaller groups, until 14 days. 3. Bone forming potentials of Teflon membrane group was higher than Nylon membrane groups, Control group has the lowest bone forming potentials. 4. New bone formation was almost ended in 42 days, and there was no difference of bone formation between Nylon and Teflon membrane group of different size. There was no difference of bone formation at final stage(42 days) between Nylon membrane and Teflon membrane of same pore size. So nylon membrane may be clinically usable in guided bone regeneration case with further studies.

• Membrane and Water Treatment
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• 제8권6호
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• pp.553-562
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• 2017

In the present study, the water desalination across the penta-graphene has been explored by using molecular dynamics simulation. The penta-graphene, a new carbon allotrope, introduced theoretically in 2015. It was shown that this carbon nanostructure is slightly stiffer against buckling in comparison with the graphene nanoribbons. The effect of radius of curvature (ROC) of the membrane, pore size, and applied pressure, on water flow rate, and salt rejection is investigated. It is shown that salt rejection, and the shape of the oxygen density distribution inside the pore can be influenced by the ROC of membrane. Finally, it is shown that the ROC, and pore size of 2D membranes, play an important role in the salt rejection.